President Barack Obama is challenging Republicans to live up to their avowed adherence for the Constitution and agree to vote on his nominee to replace late Supreme Court Justice Antonin Scalia. A key Republican is leaving the door open to taking the first step.

Despite widespread Republican insistence that he leave the decision to the next president, Obama said he had no intention of abdicating his responsibilities before leaving office early next year. He chidingly told the Senate he expects "them to do their job as well."

"The Constitution is pretty clear about what's supposed to happen now," Obama said late Tuesday before returning to Washington from California.

Fallout from Scalia's unexpected death overshadowed Obama's two-day summit meeting with Southeast Asian leaders. Obama pledged to nominate a candidate "indisputably" qualified, but Republican leaders have threatened to refuse to hold hearings or a vote on his pick to replace the conservative Scalia.

The stakes are particularly high because Scalia's replacement could tip the ideological balance of the court. Scalia's death leaves the court evenly divided between four liberal-leaning judges appointed by Democratic presidents and four-conservative-learning judges appointed by Republican presidents. The U.S. Constitution provides that any nominee put forth by Obama for the high court must be confirmed by the Senate, where Republicans currently have a 54-46 majority.

There were hints that at least some Republicans might come around. Senate Judiciary Chairman Charles Grassley said he would wait "until the nominee is made before I would make any decision" about holding hearings, boosting White House hopes for getting a third justice confirmed on Obama's watch.

With the looming nomination creating ripples in the presidential campaign, Obama sought to broaden his argument by calling the dispute emblematic of years of escalating partisan hostilities over judicial nominations. He lamented a new normal in which "everything is blocked" even when there's no ideological or substantive disagreement — and conceded that Democrats are not blameless

"This would be a good moment for us to rise above it," Obama said.

Court officials said Scalia's body will lie in repose on Friday in the Supreme Court's Great Hall, after a private ceremony. The funeral mass Saturday will take place at the Basilica of the National Shrine of the Immaculate Conception in Washington.

Chuck Grassley

Chuck Grassley, R-Iowa, seen on Feb. 10, said Tuesday he will not reject a nominee out of hand, preferring to wait and see who Obama puts forth. (J. Scott Applewhite/The Associated Press)

Since Scalia's unexpected death at a Texas ranch over the weekend, White House lawyers and advisers have been scrambling to identify potential replacements, while also devising a strategy to get a nominee confirmed.

Senate Majority Leader Mitch McConnell has said he doesn't think Obama should put a candidate forward. The Kentucky senator joined several Republicans up for re-election in declaring that Obama should let voters in November weigh in on the direction of the court through their vote for president.

Fewer lower court nominations in election years

Obama rejected that notion, insisting he will put forward a replacement and believes the Senate will have "plenty of time" to give the nominee a fair hearing and a vote. Democrats say Obama has every right and a constitutional duty to fill vacancies on the court until he leaves office next January.

The pace of judicial confirmations always slows in presidential election years thanks to reluctance by the party out of power in the White House to give lifetime tenure to their opponents' picks. In the past, lawmakers have sometimes informally agreed to halt hearings on lower court nominations during campaign season. But Obama argued that "the Supreme Court's different."

McConnell has shown no signs of shifting his opposition, and several lawmakers facing heated elections have backed him up. But the Republicans may still be searching for a strategy.

The White House has been looking for cracks in the Republicans' opposition as it deliberates on a nominee, and Grassley's remarks to home-state reporters offered the first signs of hope.

If Republicans indicate they may hold hearings, Obama would have greater reason to name a "consensus candidate," a moderate nominee that Republicans would be hard-pressed to reject. If there's virtually no chance of Republicans bending, Obama might pick a more liberal nominee who galvanizes Democratic support and fires up interest groups in the election year.

If Senate Republicans hold fast to their vow not to confirm anyone Obama nominates, the Supreme Court will operate with eight justices not just for the rest of this court term, but for most of the next one as well. High court terms begin in October, and the 80 or so cases argued in the course of a term typically are decided by early summer.

The court would be unable to issue rulings on any issue in which the justices split 4-4. Such split decisions would leave in place lower court rulings but not set any precedents.