President Obama celebrated the Supreme Court’s decisions Wednesday on gay marriage, but overall it has been a rocky term before the court for his administration, winning just more than a third of the cases in which it was involved.

Lawyers said the government traditionally averages about a 70 percent winning percentage before the high court. Its advantages are so great that the Justice Department’s chief Supreme Court attorney, the solicitor general, is dubbed the “10th Justice.”

But during the 2012-13 term, which began in October and ended Wednesday, the court rejected Mr. Obama’s arguments on property rights, affirmative action, voting rights and other issues.

“Despite some notable victories, the Obama administration has had an unusually poor batting average at the high court,” said Adam Winkler, a constitutional law professor at UCLA. “Like last year, the Obama administration lost more cases than it won.”

By Mr. Winkler’s count, the Obama administration has won 39 percent of the cases in which it has been a party in the litigation, and won 50 percent of the cases in which the government filed a “friend of the court” brief backing one side or the other.

Mr. Winkler said a good portion of the administration’s poor batting average can be traced to ideological differences between the Obama administration and the five conservative-leaning Supreme Court justices.