During the confirmation hearings for Judge Brett Kavanaugh, members of the Senate Judiciary Committee will no doubt ask him about his views on constitutional interpretation. In that light, I thought it might be useful to set out here brief descriptions of the four most common approaches to constitutional interpretation. Some of these approaches overlap in application, but they emphasize distinct interpretative priorities, and individual justices have invoked different approaches in different cases over time.

Judicial Restraint: Under this approach, which is associated with Justice Felix Frankfurter, among others, judges give broad deference to the elected branches of government. The underlying assumption is that elected officials should have the primary say both in matters of policy and in interpreting and applying the Constitution. Thus, under this approach, courts should hold government actions unconstitutional only if there is no rational justification for the action, where “rational” is understood as requiring a high degree of deference to the judgments of elected officials.

The primary argument in favor of this approach is that judges should be wary of imposing their own values and judgments on elected officials. The primary argument against this approach is that our Constitution recognizes the danger that political power can be abused, that elected officials are often tempted to misuse their authority, and that judicial review is necessary to constrain the actions of elected officials when they disregard the rights and limitations embodied in the Constitution. As Alexander Hamilton explained in Federalist 78 , constitutional protections can “be preserved in practice” only “by courts of justice,” which must “guard the constitution and the rights of individuals from the effects of those ill humours which . . . sometimes disseminate among the people.”

Originalism: This approach, which gained attention in the 1980s and has been championed by such figures as Robert Bork, Antonin Scalia, and Clarence Thomas, attempts to restrain judicial authority while at the same time addressing a perceived shortcoming of the judicial restraint approach. Originalism was designed to preserve a strong presumption of judicial restraint, except when such restraint is clearly inconsistent with the “original” understanding of specific provisions of the Constitution.

In applying this approach, most originalists maintain that the provisions of the Constitution should be interpreted in a manner consistent with what reasonable persons living at the time of their adoption would have understood the ordinary meaning of the text to be.

Defenders of originalism, usually conservatives, argue that it is preferable to the judicial restraint approach because it does not abdicate the responsibility that the Framers intended the courts to have in enforcing the guarantees of the Constitution, and that it is preferable to more “open-ended” approaches to constitutional interpretation because it constrains judges from imposing their own values and understandings on the nation through the process of constitutional interpretation.

Critics of originalism, usually liberals, argue that this approach is at war with itself because it is inconsistent with what the Framers themselves actually expected and intended judges to do when interpreting the often vague and open-ended provisions of the Constitution. These critics also note that it is often difficult to discern with any certainty the actual original intent or original public meaning of the open-ended provisions of the Constitution, and that jurists purporting to apply originalism often just assume that the original intent or original public meaning was what they themselves would have meant by the relevant language had they been the Framers of our Constitution.

Supposedly “originalist” arguments, for example, that affirmative action is unconstitutional, that gun regulations are unconstitutional, or that restrictions on corporate campaign expenditures are unconstitutional are often sharply critiqued on the ground that those views cannot in fact be reconciled with any credible understanding of original intent or original public meaning.

“Representation Reinforcement” and Footnote 4: Another approach to striking a proper balance between the need to give appropriate deference to the judgments of elected officials and the need to fulfill the central constitutional responsibilities of the judiciary is captured in the Supreme Court’s famous footnote 4 in United States v. Carolene Products, which was handed down eight decades ago. In that decision, the Court suggested that courts should exercise judicial restraint in most cases, but that there are some circumstances in which there should be “narrower scope” for the general “presumption of constitutionality.” Specifically, the Court noted that “more exacting judicial scrutiny” may be appropriate when laws are designed to manipulate the democratic political process and when they disadvantage minorities and other vulnerable groups in society. Put simply, the Court recognized in footnote 4 that courts should not be too quick to defer to the outcomes of the political process when there is good reason to believe that that process itself may have been flawed.

Following this approach, the Supreme Court has often departed from the presumption of judicial restraint when governing majorities act to disadvantage historically vulnerable groups (such as African Americans, ethnic minorities, political dissidents, religious dissenters, women, gays and lesbians, and persons accused of crime); when they use their authority to silence critics, entrench their own political power, or undermine the constitutional structure of checks and balances; and when majorities act in moments of high crisis. In such circumstances, the Court has exercised a “more exacting judicial scrutiny” in order to protect our most fundamental freedoms and guard against those malfunctions of majority governance that most concerned the Framers.

The Living Constitution: This approach to constitutional interpretation rests on the premise that the Framers of our Constitution sought not only to address the specific challenges facing the nation during their lifetimes, but also to establish foundational principles that would sustain and guide our nation into an uncertain and evolving future. Its core intuition was captured by Chief Justice John Marshall two centuries ago in McCulloch v. Maryland when he observed that “we must never forget that it is a Constitution we are expounding . . . intended to endure for ages to come, and consequently to be adapted to the various crises of human affairs.”

This approach notes that our Constitution identifies our most fundamental freedoms in very general and abstract terms: “freedom of speech,” “due process of law,” “free exercise of religion,” “equal protection of the laws,” “privileges and immunities of citizenship.” The Constitution sets forth governmental powers in similarly general terms: Congress may regulate “commerce among the several states,” Congress may enforce the Fourteenth Amendment “by appropriate legislation,” the president will “take care that the laws be faithfully executed,” and so on.

Proponents of this approach maintain that the Framers of our Constitution understood that they were entrusting future generations of jurists with the responsibility to draw upon their judgment and experience in an ever-changing world to give concrete meaning to these broad principles over time. Under this approach, the principles enshrined in the Constitution do not change over time, but the application of those principles must evolve as society changes and as experience informs our understanding.

As an example of this approach, almost all justices seem to agree that as technological means of surveillance became more sophisticated, the meaning of the term “search” in the Fourth Amendment must also change. That term has come to include invasions of privacy, like wiretapping and cell-site locational tracking, even though they do not involve a physical trespass, which was the meaning of “search” when the Fourth Amendment was adopted. Similarly, the provision of the Constitution granting Congress the power to maintain the nation’s “land and naval Forces” eventually came to be seen as authorizing an air force. And the guarantee of “equal protection of the laws” in the Fourteenth Amendment came to be understood over time as prohibiting discrimination not only against African-Americans, but also against ethnic minorities from different countries, women, and gays and lesbians, because such discrimination was seen as analogous to discrimination against African-Americans.

During the confirmation hearings, Judge Kavanaugh will no doubt be asked about which of these approaches to constitutional interpretation he embraces. His answers will tell us a lot about what sort of Justice he will be if he is confirmed.