What explains the fading 5-to-4 at the Supreme Court?

Amply demonstrating why she will be missed at the NYTimes (she accepted a buyout earlier this year and will be succeeded by national legal correspondent Adam Liptak) Linda Greenhouse wonders why so few 5-to-4 Supreme Court rulings this term:

Something is happening, clearly. The question is what. The caveats against drawing any hard conclusions at this stage are obvious. For one thing, the term is functionally only half over, with 35 cases down and 32 to come. And it is common for the hardest-fought decisions to come at the very end. The District of Columbia gun control case, the latest case on the rights of the Guantánamo detainees and a case on whether the death penalty is a constitutional punishment for raping a child are yet to be decided.

Still, there is a clear pattern in the cases the court has already decided this term. The court upheld Kentucky’s method of execution by lethal injection by a vote of 7 to 2. It upheld Indiana’s law requiring photo identification at the polls by a vote of 6 to 3. The justices voted 7 to 2 on Monday to uphold the latest federal effort to curb trade in child pornography.

All were major cases, all plausible candidates for 5-to-4 outcomes. All were government victories, hardly surprising coming from a conservative court. But even Justice John Paul Stevens, the leader of the court’s beleaguered liberal bloc, voted with the majority in all three cases. The surprise was that the government side won each so handily.

It would be too simplistic an explanation to say that the liberal justices, at least some of them, have simply given up. Something deeper seems to be at work. Each of those three cases might have received a harder-edged, more conclusively conservative treatment at the hands of the same five-member majority that controlled the last term.

She notes three areas that may have something to do with it:

- Political scientists have long observed an “election effect” which results in more consensus on the court.

- The conservative justices may have been taken aback by the public response to last term’s Ledbetter case, which placed a tight time limit on an employee’s ability to file a pay discrimination claim.

- And, perhaps most interestingly, she says that Chief Justice John G. Roberts Jr.’s early claims that he would seek consensus and lead in a modest judicial voice have been called into question by liberals and conservatives alike.

“So far this term, he has dissented only once.”