WASHINGTON — The doors to the Republican cloakroom off the Senate floor swung open and out walked Senator Ron Wyden, an Oregon Democrat who is not usually found in the inner sanctum of the majority party.
He had been buttonholing Republican colleagues, trying to persuade them that racially charged college writings by Ryan W. Bounds, a federal appeals court nominee from Mr. Wyden’s home state, were disqualifying and that he should be rejected. His crusade seemed unlikely to succeed, given that disciplined Senate Republicans have been pushing through Trump administration judicial picks with assembly-line efficiency over the heated complaints of Democrats.
But in a stunning development, the nomination of Mr. Bounds was withdrawn at the last minute on Thursday because of Republican objections, a sharp turn of events with significant implications for both the Senate and the coming showdown over the nomination of Judge Brett M. Kavanaugh to the Supreme Court.
“Today, the Senate came to its senses with respect to judges,” said Mr. Wyden, who teamed up with his home-state Democratic colleague, Jeff Merkley, to try to educate Republicans about Mr. Bounds’s writings from his time at Stanford. (Democrats cited numerous articles they considered racist, inflammatory and offensive, and also said Mr. Bounds had not been forthright about producing them.)
Mr. Bounds’s nomination was pulled after Senator Tim Scott of South Carolina, the only black Republican senator, made clear he would not vote for him because of the writings, despite a hastily arranged face-to-face meeting with the nominee. Senator Marco Rubio, Republican of Florida, quickly sided with his close friend Mr. Scott, and other Republicans also signaled that they would vote against Mr. Bounds.
His nomination was scratched to avoid an embarrassing defeat for President Trump, a rare setback in the administration’s determined march to put conservatives on federal courts around the country. Mr. Bounds was to be named to the United States Court of Appeals for the Ninth Circuit, a court dominated by liberal jurists that has been a particular thorn in the side of Mr. Trump.
The outcome underscored just how narrow a margin that Senator Mitch McConnell, the Kentucky Republican and majority leader, has to work with when it comes to Judge Kavanaugh. Because of the continued absence of Senator John McCain, the Arizona Republican being treated for brain cancer, the defection of a single Republican can doom a nominee if Democrats remain united in opposition.
And Democrats pounced on the fact that Mr. Bounds was undone by long-ago writings, saying the episode legitimized their demand that all documents from Judge Kavanaugh’s past work in government should be disclosed, even though it might be a ponderous task to produce them and take weeks to review them.
“This nomination’s defeat is a sign of inadequate vetting and excessive haste,” said Senator Richard Blumenthal, a Connecticut Democrat who sits on the Judiciary Committee. “It should stand as a rebuke to my Republican colleagues who are seeking to severely constrict review of Judge Brett Kavanaugh’s nomination to the Supreme Court. Restricting documents and time is a great mistake for lifetime judicial appointments.”
Democrats want access to hundreds of thousands of documents and emails from Mr. Kavanaugh’s service in the administration of George W. Bush, and Republicans are resisting. Senator Charles E. Grassley, the Iowa Republican who is the chairman of the Judiciary Committee, says that he won’t allow a “government-funded fishing expedition,” and notes that many Democrats have already vowed to oppose the nomination without seeing any records.
Senator Chuck Schumer of New York, the Democratic leader, has so far refused to schedule the traditional meeting with Judge Kavanaugh, and said he wanted to first see progress on an agreement over the documents. The undoing of Mr. Bounds is likely to harden the Democratic position and resolve.
The Bounds nomination was already notable because the two Oregon senators had withheld the customary “blue slip” showing their support for the nominee. In the past, such a refusal could doom a nomination because senators were uneasy about advancing judges over the objections of home-state senators, recognizing that the next time it could be them being rolled over.
But Mr. Grassley, at the urging of Mr. McConnell, has made clear that he will not allow the lack of blue slips to derail appeals court nominees over what he calls ideological and partisan reasons. Senate confirmation of Mr. Bounds would have been the first in decades — and perhaps the first ever — with no blue slip from either home-state senator. After eliminating the 60-vote filibuster threshold against judges in 2013, Democrats were now powerless to stop Mr. Bounds without Republican help.
Though the blue slip issue was not cited as a factor in the failure of the nomination, senators said that it was being discussed among themselves on the floor, and that there was relief that the showdown over respecting the arcane Senate practice had not materialized.
“We shouldn’t be walking away from special Senate traditions in this kind of cavalier way,” Mr. Wyden said.
One reason for the blue slip practice is to force the executive branch to consult with home-state senators in making judicial picks, fulfilling the “advice and consent” requirement of the Constitution. Oregon’s senators said the White House had not been sincere in trying to work with them, though Republicans said that, in their view, the administration had adequately consulted.
“Hopefully, this will send a message to the White House that you need to engage in authentic consultation if they want to have a smoother path,” said Mr. Merkley, who also praised the “courageous stand” of Mr. Scott in opposing an administration nominee who appeared headed to a lifetime seat on the bench.
The Oregon senators said they believed that the handling of the Bounds nomination would influence other nominations going forward and could provoke closer scrutiny of judicial candidates by members of both parties. The Stanford articles had been aired during the Judiciary Committee review of the nomination, and Mr. Bounds, a federal prosecutor, had apologized for them.
But they were evidently unknown to other Republican senators, who became disturbed that they were being asked to confirm him. With Democrats holding few tools to derail nominations, Republicans have been aggressively filling vacancies on the federal bench. And with Mr. Trump so dominating the political discussion, many individual nominations have been getting scant notice.
“In normal times, this should have attracted massive amounts of attention,” said Mr. Merkley, who spoke repeatedly on the floor and individually with colleagues about Mr. Bounds and the need to preserve the blue slip custom. “We were very afraid this was getting lost. I am still somewhat surprised that we had a successful outcome.”
So were many others both in and outside the Senate.