WASHINGTON — President Barack Obama accused Senate Republicans on Wednesday of putting the Supreme Court’s credibility at risk if they make good on their vow not to consider or vote on his pick to replace the late Justice Antonin Scalia. He promised to nominate a candidate anyway.

“I’m going to do my job,” Obama said.

Obama, weighing in during an Oval Office meeting, acknowledged that Republicans are under “enormous pressure from their base” to oppose his nominee. But he said if Republicans defy the Constitution by snubbing his nominee, the ability of any future president to pick judges will further erode.

“At that point, not only are you going to see more and more vacancies and the court system break down, but the credibility of the Court begins to diminish because it’s viewed simply as an extension of our politics,” Obama said after a meeting with Jordan’s King Abdullah II.

Majority Leader Mitch McConnell, R-Ky., said just a day earlier that his 54-member GOP caucus was united against taking any step in the Senate’s “advise and consent” process. The Judiciary Committee will not hold confirmation hearings for the nominee. The committee and the full Senate will not vote.

But Obama said that once Republicans are faced with an actual candidate they can examine, the situation would evolve and GOP opposition might soften. He said he hoped Judiciary Committee members would “recognize that it is their job to give this person a hearing” and then let their conscience dictate whether to approve or reject his nominee.

“I don’t expect any member of the Republican caucus to stick their head out at the moment and say that,” Obama said. “But let’s see how the public responds to the nominee that we put forward.”

Earlier Wednesday, he urged the Republican-run Senate on Wednesday to fulfill its “constitutional responsibility” and consider his Supreme Court nominee,.

Obama, in a post on the legal blog SCOTUSblog, offered his most expansive description of the qualities he is seeking in a nominee: a sterling record, a deep respect for the judiciary’s role and an understanding of how the law affects real people. He emphasized his duty under the Constitution to select justices for the high court, a message aimed squarely at Senate Republicans.

“I hope they’ll move quickly to debate and then confirm this nominee so that the Court can continue to serve the American people at full strength,” Obama said.

Obama’s rebuttal, headlined “A responsibility I take seriously,” came a day after Senate Republicans delivered an extraordinary election-year rebuff by insisting that voters November’s election and the next president hold the authority to replace Scalia.

Majority Leader Mitch McConnell, R-Ky., said Tuesday that his 54-member GOP caucus was united against taking any step in the Senate’s “advise and consent” process. The Judiciary Committee will not hold confirmation hearings for the nominee. The committee and the full Senate will not vote.

A few Republicans, including McConnell, said they would not even meet with the nominee when that person makes introductions on Capitol Hill.

“Why would I? We’ve made the decision,” said Sen. Orrin Hatch, R-Utah, a committee member.

In his post Wednesday, Obama tried to quell conservative concerns that he would choose an unabashedly liberal who would upend the court’s balance. He said he would pick someone who recognized the court’s limits and knows that a judge’s job is to interpret law, not make it.

“I seek judges who approach decisions without any particular ideology or agenda, but rather a commitment to impartial justice, a respect for precedent, and a determination to faithfully apply the law to the facts at hand,” Obama said.

The president also said the law isn’t clear in all cases that reach the high court. He said he was looking for someone whose “life experience” outside the court would allow that person to understand how decisions affect “the daily reality of people’s lives in a big, complicated democracy.”

“There will be cases in which a judge’s analysis necessarily will be shaped by his or her own perspective, ethics, and judgment,” he wrote.

Republicans are adamant they will not budge.

McConnell won unanimous public backing from the 11 Republicans on the committee, and he told reporters, “In short, there will not be action taken.”

Still, Obama said he would announce a nominee in the next few weeks.

Filling the vacancy left by Scalia’s unexpected death on Feb. 13 is crucial because the Supreme Court now has a 4-4 ideological split between justices who are usually conservative and its liberal wing. The battle has invigorated both sides’ interest groups and voters who focus on abortion, immigration and other issues before the court.

“He hasn’t seen the pressure that’s going to build,” Sen. Democratic leader Harry Reid of Nevada said when asked if he thinks McConnell might relent. “It’s going to build in all facets of the political constituency and the country.”

After meeting privately with GOP senators for the first time since Scalia’s death, McConnell and other leaders said rank-and-file Republicans were overwhelmingly behind the decision to quickly halt the nomination process.

“Why even put that ball on the field?” Sen. Pat Roberts, R-Kan., said of hearings. “All you’re going to do is fumble it. Let the people decide.”

Moderate Sen. Susan Collins, R-Maine, and Sen. Mark Kirk, R-Ill., who faces a tough re-election race this fall, are among the few who’ve voiced support for at least holding hearings on an Obama nominee. Democrats are hoping that other Republican senators facing re-election in states Obama won twice – New Hampshire, Ohio, Pennsylvania and Wisconsin – will relent over time or face retribution from voters.

Since the Senate started routinely referring presidential nominations to committees for action in 1955, every Supreme Court nominee not later withdrawn has received a Judiciary Committee hearing, according to the Senate Historical Office.

In remarks Tuesday at Georgetown University law school, Justice Samuel Alito sounded resigned to spending the rest of this year in a court whose members are locked in a 4-4 tie.

“We will deal with it,” Alito answered when asked about Republicans’ resolve to oppose anyone Obama nominates.

Associated Press writers Alan Fram, Andrew Taylor and Mark Sherman contributed to this report.