What we learned about the Roberts court

Two blockbuster cases decided in the final week of the Supreme Court’s 2012-13 term invalidated critical provisions of federal statutes. In United States vs. Windsor, the court struck down Section 3 of the Defense of Marriage Act of 1996, which defined marriage for purposes of federal law as a union between a man and a woman. In Shelby County vs. Holder, the court invalidated a key provision of the 1965 Voting Rights Act, effectively eliminating the requirement that certain jurisdictions submit proposed election-law changes to federal officials for review before implementation.

Considered together, these rulings reveal significant lessons about how constitutional interpretation works.

First, both decisions would have been almost inconceivable in the years immediately following enactment of the statutes. The Voting Rights Act, passed after epic civil rights confrontations in Selma, Ala., responded to the massive and unconstitutional disfranchisement of African Americans in Southern states. The law’s requirement that those states “pre-clear” proposed electoral changes with the federal government was a dramatic departure from conventional federalism principles, yet it was easily and almost unanimously sustained by the Supreme Court just one year after its enactment.

VIDEO: Understanding the Prop. 8 and DOMA decisions

Similarly, few people in 1996 doubted that Congress had the power to limit marriage, for purposes of federal law, to opposite-sex couples. As of that date, not a single state or a single nation permitted same-sex couples to marry. Both houses of Congress passed the measure by overwhelming majorities, which reflected the opposition to same-sex marriage of the vast majority of Americans. A Democratic president, whose election had been cheered by gay rights activists, signed DOMA into law.

Windsor and Shelby County thus illustrate how constitutional interpretation reflects changing social and political context. Minority political participation in the South has vastly increased over the last 50 years. Black and white rates of voter registration and turnout are nearly equal today, and thousands of African Americans hold elective office in Southern states (not to mention the fact that the nation has a black president). For five members of the court, such changes were sufficient to justify invalidating a congressional requirement that special restrictions apply to election-law changes in Southern states.

Similarly with regard to Windsor, in 2013 a majority of Americans support same-sex marriage, 12 states have approved it, a majority of U.S. senators and the president have endorsed it, and sophisticated models project that within only another decade, every state will have a majority in favor of it. In that context, five justices concluded that DOMA demeaned the status and dignity of same-sex couples who were validly married under the laws of their states and thus was unconstitutional.

DECISION: U.S. Supreme Court overturns DOMA

A second lesson to draw from these rulings is that none of the justices takes a consistent position on whether important social and political controversies ought to be resolved through democratic decision-making. The four conservative dissenters in Windsor expressed outrage that the court would intervene to constitutionally resolve an issue like same-sex marriage that is the subject of vigorous and ongoing political debate. Yet those same justices had no qualms about invalidating a Voting Rights Act provision that has been enacted and reenacted by Congress no fewer than five times in the last 50 years, most recently in 2006, by a unanimous vote in the Senate and a margin of greater than 10 to 1 in the House.

Similarly, the liberal justices who urged deference to Congress with regard to the Voting Rights Act did not hesitate to displace Congress’ judgment with regard to same-sex marriage. One can only conclude that while the justices don’t hesitate to invoke the virtues of democratic decision-making in an inconsistent and opportunistic fashion, this consideration has little influence on their constitutional interpretations.

Third, these rulings confirm — if confirmation was needed — that constitutional interpretation is inextricably intertwined with politics. Both rulings divided the court along traditional political lines. The conservative bloc of justices, appointed by conservative Republican presidents, voted to invalidate a provision of the Voting Rights Act that applies to a region of the country that is most reliably Republican. The provision has been used to invalidate measures — such as voter identification laws and restrictions on early voting days — routinely enacted by Republican state legislatures, and it has protected the suffrage rights of blacks and Latinos, who overwhelmingly support the Democratic party.

FULL COVERAGE: Prop. 8 and DOMA

Similarly with regard to DOMA, these conservative justices are traditionalist Catholics who almost certainly subscribe to the traditional definition of marriage as consisting of a man and a woman. That these justices’ constitutional interpretations align with their policy views is hardly a coincidence. And, of course, the same can be said of the liberal justices.

Finally, these rulings confirm that much in today’s world of constitutional law turns on Justice Anthony M. Kennedy’s inclinations. This should hardly surprise us. For the 25 years that he has been on the court, the majority of interesting and important constitutional rulings have divided the justices 5 to 4. Kennedy has been the decisive vote more often than not. On issues involving abortion, the death penalty, gay rights and the separation of church and state, he has often provided a dispositive fifth vote for the court’s liberal wing. However, on issues involving campaign finance reform, race-based affirmative action, school desegregation and federalism, he has generally sided with the conservatives.

Kennedy was the only justice in the majority in both Windsor and Shelby County. In each, he voted as he generally does: conservatively on race issues and liberally on issues involving discrimination based on sexual orientation. Possibly no other justice in American history has ever exercised so much influence in shaping our constitutional law.

Michael J. Klarman is a professor at Harvard Law School and the author of “From the Closet to the Altar: Courts, Backlash and the Struggle for Same-Sex Marriage.”