The death of Justice Antonin Scalia on Saturday plunged the Supreme Court and the nation’s political landscape into turmoil, and an immediate partisan battle began over whether President Obama should be allowed to nominate his successor.

Senate Majority Leader Mitch McConnell, R-Kentucky, said in a statement that the Senate controlled by his party should not confirm a replacement for Scalia until after the presidential election. “The American people should have a voice in the selection of their next Supreme Court justice. Therefore, this vacancy should not be filled until we have a new president,” McConnell said.

But Senate Minority Leader Harry M. Reid, D-Nev., followed McConnell’s statement with one of his own:

“It would be unprecedented in recent history for the Supreme Court to go a year with a vacant seat,” he said. “Failing to fill this vacancy would be a shameful abdication of one of the Senate’s most essential Constitutional responsibilities.”

For his part, Obama assured reporters Saturday at Rancho Mirage, Calif., that he planned to submit a nominee. “I plan to fulfill my constitutional responsibilities to nominate a successor in due time,” he said.

“There will be plenty of time for me to do so and for the Senate to fulfill its responsibility to give that person a fair hearing and a timely vote.”

With Democrats and the independents who caucus with them holding 46 seats in the Senate, Obama faces a challenge in getting the simple majority needed to confirm a nominee, and it would be an even steeper climb to rally the 60 votes needed if Republican opponents mount a filibuster.