Speaking at the close of the ASEAN summit, President Obama answered a question about the vacancy on the Supreme Court left by Justice Antonin Scalia's death. (Reuters)

President Obama on Tuesday vowed to nominate an “indisputably qualified” candidate to the Supreme Court, forcefully rejecting Republican calls that he cede the pick to his successor because the Court vacancy comes late in his presidency and in the middle of an election year.

“There’s no unwritten law that says it can only be done on off years,” Obama said at news conference marking the end of a summit with Southeast Asian leaders. The news conference focused exclusively on domestic political concerns and Mideast strife, and was dominated by questions about picking a successor for Justice Antonin Scalia, who died last weekend while on a hunting trip in Texas. “That’s not in the constitutional text. I’m amused when I hear people who claim to be strict interpreters of the Constitution suddenly reading into it a whole series of provisions that are not there.”

The president cast the standoff as more evidence of Washington dysfunction, saying the process will test whether Congress can rise above its recent history of partisan rancor to complete a fundamental constitutional task. Obama, who himself participated in an unsuccessful filibuster aimed at blocking the 2006 nomination of Justice Samuel A. Alito Jr., said “venom and rancor” have become commonplace in the Senate’s consideration of presidential appointees. He acknowledged that both parties were to blame.

“It’s not something that I have spent a huge amount of time talking about, because frankly the American people, on average, they’re more interested in gas prices and wages and issues that touch on their day-to-day lives in a more direct way, so it doesn’t get a lot of political attention,” he said. “But this is the Supreme Court, and it’s going to get some attention.”

Washington Post reporter Juliet Eilperin explains the difficulties ahead facing both Republicans and Democrats as they battle to fill the vacant Supreme Court seat left by the sudden passing of Associate Justice Antonin Scalia. (Dalton Bennett/The Washington Post)

Obama’s remarks came as a handful of key Republicans were expressing a willingness to hold hearings on a potential nominee, creating some confusion on the party’s position. Senate Majority Leader Mitch McConnell’s (R-Ky.) office said the chamber’s Republicans were united in opposing any new Obama appointee to the Supreme Court, but comments from other key lawmakers suggested the possibility of a compromise.

In a conference call with reporters from his home state Tuesday, Senate Judiciary Committee Chairman Charles E. Grassley (R-Iowa) said he “would wait until the nominee is made before I would make any decision” on whether to hold hearings on the president’s candidate. “In other words, take it a step at a time.”

Grassley, who is up for reelection this fall, added that election-year politics would not figure in his decision.

“I think I have a responsibility to perform, and I can’t worry about the election,” he said. “I’ve got to do my job as a senator, whatever it is. And there will be a lot of tough votes between now and the next election.”

Another member of the Judiciary Committee, freshman Sen. Thom Tillis (R-N.C.), noted that Republicans could not expect Obama choose a nominee in the mold of Scalia, who for almost 30 years has been the ideological leader of the court’s conservative bloc. Speaking on “The Tyler Cralle Show” on WAAV in Wilmington, N.C., Tillis said that Republicans should worry about coming across as blocking the president out of partisan spite.

“I think we fall into the trap if we just simply say ‘Sight unseen’ “ the Senate won’t consider the nominee, Tillis said, “we fall into the trap of being obstructionist.”

With Republicans struggling to stake out a unified position, Senate Democrats predicted that the GOP would cave and allow full committee hearings and a confirmation vote on an eventual nominee.

“This is a huge overreach by Leader McConnell,” Sen. Charles E. Schumer (N.Y.), the number-three Democratic leader, said in a telephone interview Tuesday.

But Republicans inclined to hold a vote on the nomination are sure to face a political backlash on the right.

FreedomWorks Foundation executive director Curt Levey said in a call with reporters Tuesday that “certain Republican senators” in the past have been “too eager to seem bipartisan right after a nominee is announced. . . . We are encouraging these senators to keep their powder dry and not say anything.”

As the political debate swirled, White House officials continued to deliberate on possible nominees. The president conferred with his aides while in California for the two-day meeting with members of the Association of Southeast Asian Nations.

Several individuals familiar with the process said Obama, a former constitutional law professor, tends to give more consideration to how a jurist might operate over decades rather than to the immediate politics of the moment.

While the White House counsel’s office has a long-standing list of possible candidates, the list is updated once a seat opens up, and the president receives dossiers on potential nominees. When the list is narrowed to half a dozen or fewer, the president conducts personal interviews.

“When he makes the final, final decision, he’s in a room by himself,” said Ron Klain, who helped spearhead the confirmation campaigns for Justices Sonia Sotomayor and Elena Kagan during the president’s first term. “I don’t think it’s possible to overstate how deeply and personally the president takes this decision. This is something he really does himself.”

The president sought to use the summit at the lush Sunnylands retreat this week to build deeper U.S. ties to Southeast Asia and make an impression on people in the region though media opportunities, including an interview Tuesday with Channel NewsAsia, an English-language television network based in Singapore. But as the extended exchange with reporters demonstrated, the future of the nation’s highest court remained paramount in many Americans’ minds.

Obama did not offer a timeline for a nomination and did not hint at whom he might select, other than to say the person would be someone “any fair-minded person, even somebody who disagreed with my politics, would say would serve with honor and integrity on the court.” He ruled out making an appointment during a congressional recess, which would not require a confirmation vote, saying he expected the process to go through the usual order.

And as the president flew back to Washington on Tuesday, preparations were underway for a public viewing ceremony for Scalia. He will lie in repose at the Supreme Court’s Great Hall on Friday, before a funeral service on Saturday, court officials said. A private ceremony will be held at 9:30 a.m., and a public viewing will be allowed from 10:30 a.m. until 8 p.m.

The following day, family and friends will gather for his funeral Mass at the Basilica of the National Shrine of the Immaculate Conception in Washington, court officials also announced Tuesday. The funeral Mass will be celebrated at 11 a.m. Saturday and will be followed by a private burial.

The last time a similar ritual played out in Washington was a little more than a decade ago, after the death of the late chief justice William H. Rehnquist. Rehnquist’s casket was carried in by a group of pallbearers that included his former clerk John G. Roberts Jr., who at the time had been nominated but not yet confirmed to succeed him as chief justice.

Mark Berman, Paul Kane and Steven Mufson contributed to this report.

Funeral plans

Friday: Scalia will lie in repose in the Court’s Great Hall. A private ceremony will take place at 9:30 a.m., and the public will be allowed in from 10:30 a.m. to 8 p.m.

Saturday: Family and friends will gather for a funeral mass at 11 a.m. at the Basilica of the National Shrine of the Immaculate Conception. This mass will be followed by a private burial.