With the conservative bloc so clearly in control, what leverage could the liberals possibly have? Recall the pledge that Chief Justice John G. Roberts Jr. made, both in his 2005 confirmation hearing and in the early months of his tenure, to seek consensus and to lead the court in speaking in a modest judicial voice. That was not how the last term looked, as the majority took aim at precedents and appeared to have in mind an agenda much more ambitious than simply calling balls and strikes.

Indeed, much of the commentary on the court’s performance during the last term was harsh, and it came not only from liberals. Judge Richard A. Posner, the conservative icon who sits on the federal appeals court in Chicago, offers some pointed and unusually personal criticism of Chief Justice Roberts in his new book, “How Judges Think,” published this year by Harvard University Press. The chief justice’s self-description during his confirmation hearing as a simple baseball umpire might have been a “tactical error” for one who evidently “aspires to remake significant areas of constitutional law,” Judge Posner writes, adding:

“The tension between what he said at his confirmation hearing and what he is doing as a justice is a blow to Roberts’s reputation for candor and a further debasement of the already debased currency of the testimony of nominees at judicial confirmation hearings.”

Such words from Richard Posner would cause any member of the court, let alone a relatively new and young chief justice who undoubtedly admires him, to swallow hard.

The court’s modulated tone may also stem from the fact that this is an election year. Lee Epstein, a political scientist and law professor at Northwestern University, said that political scientists had long observed an “election effect” on the court that results in more consensus and fewer 5-to-4 decisions during an election year than in the preceding term.

“Of course, lots of things could explain this, but the pattern is pretty interesting,” Ms. Epstein said in an e-mail exchange, adding that the justices “probably don’t want to provoke controversy, or become an issue, during the election  especially an election with a highly uncertain outcome.”

Perhaps the conservative justices were taken aback by the public response to the Lilly Ledbetter case, a 5-to-4 decision in an employment discrimination case last term that placed a tight time limit on an employee’s ability to file a pay discrimination claim. The decision led to Congressional hearings during which the court was denounced as out of touch with the reality of women’s working lives. A bill to overturn the decision failed in the Senate, but came close.

Whether as a direct result, the court adopted a notably different tone in an employment discrimination case decided in February. The court voted 7 to 2 to excuse an employee’s failure to file the proper form to initiate an age discrimination case. With only Justices Scalia and Clarence Thomas dissenting, that case, Federal Express Corp. v. Holowecki, produced one of the term’s few liberal victories. Another closely watched employment discrimination case ended, surprisingly, with a unanimous decision that avoided drawing the clear line that the two sides were arguing over.

None of this is to suggest that whatever strategic decisions the justices are making are being made collectively. The court is by its nature an atomistic institution, its actions the aggregation of determinedly individual decisions. But if any one individual is smiling, it is no doubt Chief Justice Roberts. By this time last year, he had cast seven dissenting votes. So far this term, he has dissented only once.