We certainly talk about U.S. constitutional law as if it is law. There are Constitutional Law classes in law schools. Constitutional law is often the basis for claims made in litigation—by people alleging police brutality, for example, or by criminal defendants who say that the evidence against them was illegally obtained, or by protesters who believe the government has denied them the freedom of speech. Lawyers make arguments to judges about constitutional law. There is an authoritative text: everyone agrees that the Constitution is “law” (although they disagree about the implications). Precedents also matter, and they are cited, distinguished, and elaborated in a way that more or less resembles the way precedents are used in other areas of the law. In all of these ways, constitutional law does not seem very different from many other kinds of law, except that ordinary non-lawyers may know more about constitutional law than they do about, say, the law administered by the Federal Energy Regulatory Commission.

And yet the suspicion lingers that constitutional law is not really law. Usually this skepticism takes the form of saying that constitutional law is really just a mask for politics.¹ Of course one might ask: Why does it matter whether we classify constitutional law as law or politics; isn’t this just a terminological question? But it does seem to matter, for at least two reasons. One is just that it would be good to understand what we are doing. To the extent that constitutional law is an significant part of U.S. political life, it is perhaps worth being clear about what kind of institution constitutional law is: whether it is just another form of politics, or whether it has something important in common with distinctively legal institutions.

The second reason is more practical. When people purport to be engaged in law, as opposed to politics, we have different expectations of them: they are not supposed to act in (p. 830) the same way as people who are simply trying to accomplish political goals. Certain kinds of arguments and motivations that are acceptable in politics are not acceptable in law. If constitutional law is law, then we are entitled to have those expectations about people who are engaged in some aspect of the practice of constitutional law. The question about the nature of constitutional law is one about people who make claims—or, in the case of officials, decisions—about what the Constitution requires: Must they conform to the norms of legal argument, and can they be fairly criticized if they do not? That certainly seems to be a question worth addressing.

All of this suggests that the way to consider whether constitutional law is law or politics is not to try to come up with an abstract definition of the two domains. Any such definition would be controversial, of course, and would risk being arbitrary or question-begging, if it just defined constitutional law as being on one or the other side of the line. Instead the way to approach the issue is to compare constitutional law to practices that are undoubtedly political (if anything is political), on the one hand, and then to practices that are undoubtedly legal (if anything is)—and to see what constitutional law has in common with each.

I will begin with the skeptics’ arguments that regard constitutional law as just disguised politics. Then I will consider possible rebuttals to these skeptics. I will conclude that the skepticism is generally mistaken—that constitutional law is in fact law, in the most important respects. Part of the reason for the skeptics’ mistake may—paradoxically—be a tendency to identify constitutional law too closely with the document that is called the Constitution, and a resulting excessive disillusionment when it becomes apparent that there is much more to constitutional law than that.

But the first step is to understand the skeptics’ view that constitutional law is just politics. Several things make that view plausible.

1.  The Issues Are Political

Many constitutional issues involve matters that are highly controversial political issues. Tocqueville famously said that “[s]carcely any political question arises in the United States that is not resolved, sooner or later, into a judicial question.”² Now this is not really true.³ There are many important political issues that even Supreme Court justices would not touch. The courts usually stay far away from most foreign policy issues, for example. Even with regard to domestic concerns, courts address only peripherally such issues as “fuel prices, the minimum wage, income taxes, the estate tax, Social Security, inflation, [or] interest rates. …”⁴—and that is just a partial list. But still, in most years the Supreme Court will issue decisions on topics that are also the subject of great controversy and political debate: affirmative action, gun control, abortion, religious freedom, the rights of gay people.

Those decisions influence and often limit or condition the political debate. They can confer legitimacy on what the federal or state governments have done; they establish (p. 831) boundaries beyond which the government may not go; they can give a rhetorical boost to one side in an ongoing political debate. So it is easy to conclude that what the Supreme Court is doing is not all that different from what politicians do. And when one considers that the Supreme Court, unlike most courts, has nearly unlimited power to refuse to decide a case at all—and can use that power to avoid (or engage) politically controversial issues⁵—the conclusion that the Court is an essentially political institution becomes even more plausible.

2.  The Document Is Vague

A second reason that constitutional law does not seem like real law is related to the first. Many of the provisions of the governing document—the U.S. Constitution—are famously vague. They refer, for example, to “unreasonable searches and seizures,” or “the free exercise of religion,” or “the equal protection of the laws.” If your idea of law is a detailed regulatory code in which you can look up the answers, with only occasional and accidental vagueness, then the Constitution does not look like law. And these vague provisions seem to invite judgments that are in important ways political—about what is reasonable police behavior, or about the proper role of religion in affairs of state, or about what constitutes equality.

Even apart from the particular provisions of the text, the Constitution has given rise to a rhetoric based on ideas derived from the particular provisions. That rhetoric can be mobilized on almost any side of almost any issue.⁶ For example, the Constitution, arguably, embodies a commitment to a strong central government; it was, after all, drafted to replace the Articles of Confederation. But then the Constitution arguably embodies a commitment to protecting the prerogatives of the states: their power, under the Constitution, is residual; the federal government has only those powers that are granted to it. Or is the Constitution really concerned not with the federal government or the states but with protecting individuals against every government, as evidenced by the Bill of Rights and other rights-protecting provisions? That, too, is a plausible position. When every side can invoke constitutional rhetoric in support of its political position, it begins to seem that that is all the Constitution is: a source of political rhetoric available to be used opportunistically.

3.  The Judges Are Political

A third source of the belief that the Constitution is politics, not law, derives from what happens when that vague text gets interpreted. It does, of course, get interpreted, by state and federal courts and ultimately by the U.S. Supreme Court, and those interpretations resolve at least some of the vagueness of the text. But a substantial body of political science literature is devoted to showing that those supposed interpretations reflect the judges’ (p. 832) and justices’ political views.⁷ This literature often seems to say that judges simply impose their policy views, without regard to legal materials; on closer examination, the claims are actually more qualified than that.⁸ But it is a cliché—beloved of journalists, but that does not make it false—that there are “liberal” and “conservative” justices on the U.S. Supreme Court. Some studies suggest that lower court judges’ political affiliations predict their votes on a range of cases.⁹ All of this makes it look like constitutional law is just rhetorical garb for political decisions that happen to be reached by judges.

4.  The Politicians Are Judges

There is a fourth and slightly more subtle reason to question whether constitutional law is really law. Many questions of constitutional law get settled, without the courts’ becoming involved, by the president and Congress—undeniably political actors. Presidents can be impeached and removed from office for “high crimes and misdemeanors.” The question of what kind of misconduct falls into that category certainly looks like a question of constitutional law, but it will not be settled by the courts. It will be settled in Congress, in the process of an attempted impeachment of a president and, if he is impeached, of his trial. A person would have to be pretty naïve to believe that that was strictly a legal process with politics playing no role. Similarly, if the president and Congress differ about whether the president has authority to order military action abroad, that dispute will be settled between the political branches, without the courts’ becoming involved. And again, while the protagonists will invoke the Constitution, politics is sure to play a role.

More routinely, the executive branch makes decisions—about electronic surveillance, for example—that as a practical matter will not be reviewed by any court, either because the decision remains secret, or because the matter will become moot before a court can hear it, or because no one will have standing to challenge it. Those decisions will often unavoidably require answering a question about people’s constitutional rights. But the decisions will be made by elected officials or by people who are serving an elected official; in all likelihood, political views and interests will affect the decision. And then there are the many implicit decisions about constitutional issues made by Congress and state and local governments when they enact laws or adopt other measures that will never find their way into court because litigation is not worth the time and trouble. For practical purposes, these issues will be decided by a process that looks like ordinary politics.¹⁰

(p. 833) 5.  The Constitution Is a Mere Parchment Barrier

This was James Madison’s famous concern about a bill of rights: that it might be nothing more than a “parchment barrier[].”¹¹ The Bill of Rights would not be able to prevent violations of individual rights if the government were determined to violate them. Madison thought that the best a constitution can do is to establish institutions that might channel the political clash of interests in a way that will end up protecting individual rights.

Madison’s argument can be generalized. The idea is that constitutional law, in the end, cannot stand up to political forces. Political actors will comply with constitutional law (and no doubt invoke its authority) when it is in their interest to do so; but when it is not in their interest to do so, they will brush the parchment barrier aside. Whatever constitutional law might say, in the end the play of political interests will be decisive.¹²

One common version of the “parchment barriers” argument pretty clearly proves too much. The idea behind the “parchment barriers” claim is that constitutional law is just parchment because when there is a conflict, politics, not law, will really decide who wins and loses. But once you talk about “politics,” you are talking about institutions. People exercise political power by getting their way through certain institutions. And it is the constitution, or other laws (written or unwritten), that set up those institutions and define how they work and what they can and cannot do. If the constitution and the laws are really just easily ignored “parchment,” then there are no functioning institutions—or at least no stable and robust institutions—and politics itself, as we normally understand it, becomes impossible.

For that reason, Madison’s idea that the federal and state governments can be structured in a way that would protect individual rights assumes that constitutions are not just parchment. Otherwise the institutional arrangements would simply be disregarded.¹³ So the idea must be that certain forms of constitutional law—those that explicitly protect rights, maybe, as Madison suggested; or those that are not enforced by the courts—are less efficacious. With respect to those aspects of constitutional law, outcomes will be determined by political forces, not by any distinctively legal forms of reasoning or adjudication. That may be true, but right away that makes the “parchment barriers” argument much less powerful, at least if the objective is to show that constitutional law is really just politics. At least certain kinds of legal restrictions are not just parchment but can limit and channel politics. Those restrictions, it seems, function as law.

The argument that constitutional law is a parchment barrier is sometimes linked to a related claim: that for constitutional law, unlike supposedly real law, there is no external authority with enforcement power. In this way, constitutional law seems to resemble international law—and it is a familiar point that international law is only (p. 834) very questionably a form of law.¹⁴ Private law is enforced by the government. But constitutional law, like international law, is directed at government actors; no enforcement authority stands above them. That is an important way, the argument goes, in which constitutional law is merely a parchment barrier and not like more easily recognizable forms of law.

6.  The Constitution Reflects Popular Opinion

Finally, it seems to be a truth repeatedly rediscovered that Supreme Court decisions about the meaning of the Constitution never venture too far away from public opinion, or at least elite opinion.¹⁵ Particular decisions of the Court’s may be more or less unpopular; a decision may antagonize a regional or cultural group. But it is rare for decisions to be highly unpopular throughout the country, and when they are, they generally do not survive. It is easy to see why this is so: justices and judges are appointed by the president and confirmed by the Senate. They are unlikely to have views that are too far out of the mainstream. They also are unlikely to have had such successful careers unless they had pretty well-developed political antennae themselves. So one would not expect the Supreme Court to be politically tone-deaf too often.

Once again, this claim should not be overstated. It would be a mistake to suppose that there is a kind of mechanical connection between popular opinion and judicial decisions. But it would also be a mistake to suppose that constitutional law is an autonomous enterprise that operates in isolation from the kinds of currents of public opinion that determine the shape of politics.

In fact, the point runs deeper than a rough correspondence between judicial decisions and popular opinion, resulting from the way judges are selected. Sometimes constitutional issues get settled by popular opinion without the intercession of judges. This is most obvious in periods of upheaval. The unconstitutionality of slavery was settled by the Civil War, and the Union succeeded in the Civil War because there was at least enough popular support to sustain the war effort. But in less dramatic ways, too, public opinion can be the court of last resort when it comes to the Constitution.¹⁶ The constitutionality of the New Deal expansion of federal power, for example—one of the central developments of twentieth-century constitutional law—was essentially settled by public opinion, reflected in the repeated re-election of Franklin Roosevelt. The Supreme Court tagged along.¹⁷

1.  Settled Law: The Text

Despite all of that, constitutional law turns out to be not very different from what would be universally recognized as law—at least in a lot of ways. You can begin with the words of the document. The provisions that give rise to litigation are often vague, but other provisions are not. There is one president and there are two Houses of Congress. Each state gets two senators. A bill cannot become law unless it passes both Houses of Congress and is signed by the president, but the president’s veto can be overridden. The president leaves office at noon on January 20 following an election.

These provisions are relatively clear—they rarely give rise to litigation or to controversies about how they should be interpreted—and they are important. Things would be different, and not in a good way, if the Constitution did not have a clear provision about when the president’s term ends. Presidents do, in fact, leave office on January 20, and they do so because the law—the Constitution—says they have to.

If anything, the relationship between politics and law here is the opposite of what is depicted by people who point to the predictable political leanings of judges and say that constitutional law is just politics dressed up in legal rhetoric. Sometimes, instead of politics determining what the law is, the law determines what will be politically acceptable. Why would it be untenable for a president to try to continue to exercise the powers of the office after January 20 (barring some monumentally extraordinary circumstances)? Obviously public opinion is a big part of the reason, but public opinion crystallizes around January 20 as the date the president must leave precisely because that date is specified in the Twentieth Amendment. If the Constitution specified some other date, that date would become the focal point for the political pressures that effectively make it unthinkable that a president would try to extend his term. In some Supreme Court cases it might seem that politics is determining the legal outcome; here it is the opposite. The law determines what is politically acceptable.¹⁸

2.  Settled Law: Beyond the Text

It is not just that sometimes the text of the Constitution is clear. Routinely, constitutional law is clear even when the text is not. The law has been settled by precedent or tradition. The government may not imprison people just for criticizing government policies. You might think that the First Amendment makes that clear, but it does not; a few years after the First Amendment was added to the Constitution, Congress (which contained many of the participants in the Constitutional Convention) enacted the Alien and Sedition Acts, which authorized criminal punishment for criticism of the government. Neither states nor the federal government may segregate schools or other public facilities by race in a way (p. 836) that discriminates against minorities. The text does not explicitly say that either. But these points are as completely settled as anything in American law. They have been settled by a combination of court decisions and traditions that have come to be accepted—as part of constitutional law—by the political culture.

Maybe more to the point—if the question is whether constitutional law can be reduced to politics—are constitutional principles that are certainly at odds with the political views of some judges but that are so thoroughly settled that no judge, whatever her politics, would think of disturbing them. In these cases, we do not even register that the judges are acting in ways that are inconsistent with their political views. No Supreme Court justice would vote to declare a provision of the income tax unconstitutional because it was too favorable to wealthy people—or because it distributed wealth in the other direction, from rich to poor (although today maybe that is a less certain example)—however much such conclusions might be aligned with one or another justice’s political views. The text, by the way, is not what makes this unimaginable. The takings clause of the Fifth Amendment might be used (and has been used, in the academic literature) to attack the progressive income tax; the equal protection clause of the Fourteenth Amendment could be used to require greater equality of income or wealth (by concluding, for example, that “equal protection of the laws” includes equal protection from the vicissitudes of the market). The text of the Constitution has been used (or abused) in ways that are, as a verbal matter, more questionable than that. But the traditions and precedents are so well established that rulings such as these are not within the realm of reasonable argument. There are many similar examples. The constitutional issues do not even seem like issues because they are so well settled.

Then there is another category of cases, more characteristic of the day-to-day work of constitutional law. I said earlier that, if your model of law is a detailed regulatory code, then constitutional law may not look like law. But in fact, in many important areas, constitutional law actually is more or less like a detailed regulatory code. One of the classically vague provisions of the text—the Fourth Amendment’s prohibition against unreasonable searches and seizures—provides an example. It is true that there are unsettled Fourth Amendment issues, and some of them—notably those concerning electronic surveillance for national security purposes—seem to be at the heart of highly political debates. Other unsettled issues are less controversial but do require judgments about policy issues—the relative importance of law enforcement and personal privacy—that are typical of political debates.

But at the same time, police officers on the street actually have a pretty good idea of what the Fourth Amendment does and does not allow them to do. The rules that govern them can be reproduced in a manual. No doubt compliance is not perfect, to say the least, and in many places the law on the street is very different from what is in the manual. But that is not a distinctive feature of constitutional law. The law of torts is in the hands of insurance adjusters; merchants and firms that deal with each other may have elaborate norms that go beyond the relevant legal rules of commercial law.

The body of law derived from the Fourth Amendment is mostly the result of judicial decisions; the vague words of the Fourth Amendment are the foundation, but the law is really determined by precedent. Political considerations undoubtedly enter into the formulation of the precedent. But the result, on the ground, is often something quite unmistakably legal.

(p. 837) This point—that in some respects constitutional law is quite clear and not subject to political manipulation, either because of the text or because of precedent—is not a complete answer to the skeptics who think that constitutional law is really just politics by another name. It would answer an extreme form of skepticism that insisted the constitutional law was nothing but politics. But most of the skeptics take a more qualified view, at least when they are being sensible.¹⁹ They acknowledge that many cases are clear. But when the law is not clear—that, they say, is when it becomes dominantly political. And when the political winds shift, previously settled legal positions can become controversial, or vice versa. So although there may be a large body of day-to-day constitutional law that is recognizably legal, the most prominent displays of constitutional law—notably in Supreme Court decisions—are, on this skeptical account, highly political. I will address that more tamed form of skepticism in part 4 of this section; I do not think it makes the case that constitutional law is not law. It may just mean that we have unrealistic expectations about law in general.

3.  Parchment Barriers and Law outside the Courts

The example of police officers and the Fourth Amendment may seem (and may be) naïve. In some places, surely, and maybe commonly, the effective law for police officers is not what is in the manual; it is what they can get away with. And although the courts and other recognizably legal institutions are part of the police officers’ world, they are a peripheral and episodic part.

To whatever extent that is true of police officers, it is undoubtedly true that many constitutional questions are effectively resolved outside of the courts. One of the skeptical objections is that constitutional issues are often resolved, in practice, not by judges, but by politicians or people appointed by politicians—by members of Congress and state legislatures, or by federal, state, or local officials. When, as will be true in a nontrivial number of instances, those officials’ actions are not reviewed by courts, the officials will be free to act out of their political interests. If there is no effective enforcement authority that can compel them to obey constitutional norms, the argument goes, then in what sense are those norms truly legal? They are merely hortatory, probably just parchment barriers, or, at best, like the questionably legal norms of international law.

To put the point another way, the problem with constitutional law, according to this form of skepticism, is that it is law directed at government officials (a characteristic it shares with public international law). When law is directed at private parties, it can be enforced by the government. That is how we know it is law. But when “law” is directed at government officials—as constitutional law is—there is no ultimate enforcement power. That is what makes constitutional law a mere parchment barrier and not really law—or so it is argued.²⁰

Seen from one angle, this argument—that you cannot have law without an ultimate authority to enforce it against everyone—cannot be right. The reason is that in any legal system, there is some court of last resort, and, by definition, no one can enforce the law against that entity. Even the most conventional, law-like body of law will, in the end, be (p. 838) enforced by some court from which no appeal can be taken. The only limit on the judges of that court will be their own commitment to following the law. If the last resort, in practice, is not to a court but to some other official, that official is in the same position as a court would be: we have to rely on her commitment to the law. That is true of constitutional law—in the end, we have to rely on the conscientiousness of the Supreme Court, or of some lower court if a case does not get to the Supreme Court, or of some other official if the case does not get to court at all. But the same thing is true of all law.

The intuition that constitutional law is different stems, I think, from an idea about law that is superficially appealing but ultimately incorrect. Historically, one way of thinking about law—associated with Hobbes and Austin—is that law is the command of a sovereign who just exercises her will. The sovereign herself is not bound by law. If you think of law that way, then it makes some sense to draw a distinction between private law—the law governing the behavior of private entities and relations among them—and constitutional law, which governs the government itself. The sovereign is the final authority for private law. But the sovereign, in this conception, has no obligation to act according to the law. Because the sovereign is the highest authority in the government, law, therefore, cannot ultimately control the government. And because constitutional law is supposed to control the government, it cannot truly be law.

The problem is that this way of thinking assumes that there is, in our system, a sovereign that is acting outside the law and simply dictating results. But that is not the way government officials in our system purport to act, or are supposed to act, or think of themselves as acting. They are expected to act according to the law, and they acknowledge a duty to do so.²¹ Whether they do act that way, in fact, is of course a more complicated question. Perhaps, in practice, judges and other officials disregard the obligations imposed on them by constitutional law more often than they disregard their obligation to resolve private disputes according to law. But it is not obvious that that is true—officials might care deeply, for personal or political reasons, about the outcome of private disputes. And, more to the point, there is nothing about the intrinsic character of constitutional law that makes it less law-like than private law.

Also, once we recognize that a court of last resort is subject to no authority except its own conscientious sense of what the law requires, the fact that decisions about constitutional law are often made by non-judges becomes less problematic, at least in theory. It is true that decisions about what the Constitution requires will often be made by legislatures or executive branch officials, with no effective judicial review. But those officials are simply in the same position as the judges of a court of last resort. They have an obligation to follow the law—judges always acknowledge that (even if they do not follow through) and non-judges should acknowledge it too—and the fact that there is no effective authority above them does not mean that that obligation ceases to exist. And, in fact, officials in the legislative and executive branches will sometimes engage in debates about constitutional issues that are every bit as explicitly and distinctively legal as the arguments that are made in court.²²

(p. 839) Is constitutional law, then, a parchment barrier? In a sense, yes: its efficacy ultimately depends on the willingness of officials to follow the law even when no one can penalize them for not doing so. But all law is a parchment barrier, in that sense. At some point, we will probably have to rely on the conscientious commitment of some official. Perhaps there is some further enforcement mechanism—social pressure from the officials’ peers, or popular pressure. In a well-functioning system, those pressures will surely exist. Or there may just be an implicit bargain among self-interested actors.²³ But all of these things are true both of constitutional law and ordinary, day-to-day law. They do not give us a reason to doubt that constitutional law is in fact law.

Having said all of that, there remains something about constitutional law outside the courts that seems to make it less like law than the constitutional law that courts enforce. When Congress or the executive branch of the federal government decides constitutional issues that the courts will not review (as in the examples I gave earlier: whether the president has the power to send troops into conflict, or what justifies impeaching an official and removing her from office), the question of constitutionality seems inextricably political, not just in practice but in theory as well.²⁴ To be clear, “politics” here does not mean calculations of political advantage—a conscientious official can eschew those—but judgments about high-level policy, about the proper functioning of the government, that do not seem distinctively legal. In deciding these constitutional questions about presidential or congressional power, there is often no clear point at which politics, in that sense, leaves off, and law takes over—no matter how conscientious the decision-maker is. To some extent, as I will discuss shortly, this is true of constitutional law in the courts as well—and it is true to some degree of law generally. It does not mean, even in this limited setting, that constitutional law is not law at all. But outside the courts, the line between politics (in the sense of good policy) and constitutional law does seem to be especially hard to define. And, although this is a matter of degree, that does seem to be a distinctive feature of constitutional law.

4.  Constitutional Law, Common Law, and Politics

When it comes to constitutional law—maybe law generally—there seems to be only a fine line between idealism and skepticism. If you start out thinking of law as an essentially autonomous, self-contained system that yields distinctively legal answers uncontaminated by the kinds of judgments that are common in politics, then you are sure to be disillusioned, especially by constitutional law. And then it is easy to go to the other extreme and wonder if the “law” part is just rhetorical cover for an essentially political enterprise. The (p. 840) raft of studies that I mentioned earlier—documenting the extent to which judges’ politics predict their decisions—certainly does not help.

Part of the reason constitutional law seems especially vulnerable to this claim is that (as I noted earlier) it deals with many of the same questions that are the subject of political controversy. But part of the reason may also be the identification of constitutional law with the famous text. Anyone can pick up the Constitution, read it in a half an hour, paraphrase or even recite some of the most famous provisions. It is tempting to think that, although its words might need some interpreting, the Constitution is basically all right there, in one’s hand. And then when arguments about fairness or social policy start playing a role in deciding what the Constitution requires, it seems that the serpent has entered the garden and the whole project of deciding issues according to law has failed.

Even if constitutional law were simply a matter of working with the words of the document, that would be the wrong inference to draw. But in fact U.S. constitutional law is not just about the document. Some things, as I said, are settled, once and for all, by the document. But those tend to be legally uncontroversial matters, not the kinds of issues that people litigate about and that therefore generate “political” arguments about fairness and good policy. When it comes to the parts of constitutional law that are controversial, a better model is not the close reading of the authoritative text, but rather the common law.²⁵

The common law is based on precedent, broadly conceived: precedent that includes not just judicial decisions but what might be described as traditions, or customs, or nonjudicial precedent.²⁶ Constitutional decisions made outside of the courts—while, as I said, less clearly legal than judicial decisions—routinely rely on precedent, judicial and otherwise. If, say, there is a dispute between Congress and the executive branch over whether an executive official should be required to testify about internal deliberations, both sides can be counted on to invoke earlier instances in which similar disputes arose. And both sides will be careful about the precedents they will set. This is one reason for saying that, even outside the courts, constitutional law is not just politics. In the courts, it is even clearer that precedents play a crucial role in deciding constitutional issues, as they do in the common law.

The common law is as law-like as anything. It was the dominant form of law in England and then in the United States for many years. Statutes have displaced the common law to some degree and have regulated areas that the common law left alone, but the common law is still an undeniably important part of our legal system. And judgments of fairness and social policy—the kinds of things that cause people to question whether constitutional law is really law—have always been a part of the common law. There are, of course, routine common law cases in which the precedent is clear and those kinds of judgments need not be made. More important, many matters do not even turn into cases because the precedents are so clear that no one would think to litigate about the issue. In those ways, constitutional law is much like common law. Some things are settled, sometimes by the text of the Constitution (which has no obvious counterpart in the common law) but often by precedent. The Fourth Amendment example I discussed earlier is an instance of that.

Arguments about fairness and good policy have always been a part of the common law. When precedents are unclear, or when they point in different directions, judges shape the (p. 841) law in the direction that seems better as a matter of morality and policy.²⁷ That is what happens with constitutional law, too. Many things are settled. Even when things are not settled, the range of disagreement is often narrowed by the text of the Constitution or by the precedents. The kinds of things that people call “political” operate in the interstices—just as they do in the common law. Perhaps there are differences in degree between constitutional law and the common law (although it is not clear how one would measure that). But in the basic way it operates, constitutional law is as law-like as the common law.

Once we understand constitutional law this way—as a body of law that, like the common law, is settled in many ways but does permit “political” judgments to play a role—we can be a lot less troubled by the studies showing that judges’ decisions in a certain range of cases line up with their political views. Those studies focus on the most controversial issues—those on which judges disagree. There is a large area of agreement in which differences in ideology will not matter. And there are all the non-cases that never get to court because the law is so clear.

None of this is to say, of course, that ideology is unimportant. The decisions in the controversial cases can be important, and those decisions—because they may turn in part on judgments about how fair or sensible a particular outcome is—will often be influenced by a judge’s ideology or political views. That is what the empirical studies show. But that sort of limited influence does not disqualify constitutional law from being law, because a comparable kind of influence is characteristic of common law areas that are unreservedly classified as law. The apparently ideological character of the most prominent decisions does not set constitutional law apart. In the most important ways, constitutional law is law.