The harmony will dissipate in the final weeks of the term, which will probably conclude in late June. It is the divisive and hard-fought decisions that take the longest to produce, as the justices exchange draft opinions and respond to one other in evolving majority opinions, concurrences and dissents.
The marquee decisions of the term — on affirmative action, voting rights and same-sex marriage — will almost certainly be closely divided on the core issues. But the overall percentage of unanimous decisions is unlikely to drop to 40 percent, the average rate for full terms in recent years.
For now, consensus reigns. That is partly because some of the recent decisions were decidedly minor. One, concerning a towed car, would not have been out of place in small claims court or before Judge Judy. Another, about the meaning of the word “defalcation” in the Bankruptcy Code, must have made Justice Stephen G. Breyer, its author, wonder what he had done to deserve the assignment.
But the justices were unanimous in significant cases, too. They let Monsanto protect its patented genetically modified soybeans and allowed American companies credits for some taxes paid abroad. Both times, the sums at stake were easily in the hundreds of millions of dollars.
The recent unanimous cases are noteworthy for a second reason: many truly speak with a single voice. The court led by Chief Justice John G. Roberts Jr. has set records for faux unanimity, where the justices agree on the result but barnacle the majority opinion with concurrences expressing caveats, interpretive glosses or wholly different rationales.
The recent unanimous cases are different. In five of the six, there was just one opinion.
Such authentically unanimous decisions are built to last. By contrast, when the justices agree on the result but disagree about the reasons for it, the majority opinion has less force. Pamela C. Corley, a political scientist at Southern Methodist University, wrote a 2010 book on Supreme Court concurrences and found that majority opinions undermined by such concurrences are less likely to be followed in lower-court decisions and in later ones from the Supreme Court.
How do the same justices who issue the bitterly contested decisions in headline-grabbing cases manage to agree so often?...