“I BELIEVED he was going to rape me,” Christine Blasey Ford said as she began her Thursday testimony before the Senate Judiciary Committee, detailing allegations of sexual assault against Supreme Court nominee Brett M. Kavanaugh. She said she is “100 percent” certain the assailant was Mr. Kavanaugh. Mr. Kavanaugh denied the charges “immediately, categorically and unequivocally,” at times choking back tears.

Predictably, and as a practical matter, this left the Judiciary Committee, the powerful emotions of the day notwithstanding, in about the same place it started. Ms. Ford presented a credible accusation of sexual misconduct from their teenage years. Mr. Kavanaugh offered a forceful denial. The logical next step would be to take the time to see if an investigation can bolster either contention. Yet Republicans on the committee seemed more aggrieved by the Democrats’ delay in forwarding Ms. Ford’s allegation than interested in getting to the bottom of it.

On one secondary but important matter, it was possible to draw a conclusion. Mr. Kavanaugh contended that “this whole two-week effort has been a calculated and orchestrated political hit, fueled with apparent pent-up anger about President Trump and the 2016 election” and an act of “revenge on behalf of the Clintons.”

But he provided no evidence for his angry charge, and certainly Ms. Ford’s testimony did not support conspiracy theories. On the contrary, she explained she tried to relay her allegations to political leaders before Mr. Trump tapped Mr. Kavanaugh, so that the president could consider another judge of equal qualifications, refuting suggestions that she is part of a Democratic plot. She was more than supportive of reopening the FBI background check. “I wish that I could be more helpful, and that others could be more helpful and that we could collaborate to get at more information,” Ms. Ford said.

The inadequacy of the Judiciary Committee’s process was most glaring in the absence of Mark Judge, whom Republicans refused to subpoena. Ms. Ford has said Mr. Judge was in the room when the alleged assault occurred; on Thursday, she provided a few fresh details that almost certainly would have sent professional law enforcement agents in new investigative directions if they had the time and mandate. Mr. Judge has denied knowing of or being present for any assault but has also declined to offer any more information. When Sen. Patrick J. Leahy (D-Vt.) asked Mr. Kavanaugh about Mr. Judge’s writing on drunken high school antics, the nominee told the senator, “You’d have to ask him.” “I would like to,” Mr. Leahy responded.

Americans could only watch with sadness. If he is the victim of some terrible case of mistaken identity, Mr. Kavanaugh’s anger is understandable, but his partisan conspiracy-theorizing was hardly becoming of a potential Supreme Court justice. Ms. Ford, whose life and family have been upended, deserved better than the condescension shown by a number of Republican senators and, more to the point, their unwillingness to vet her claims.

In truth, there is still plenty of time. Any deadline has been artificially imposed by the Republican majority for purely partisan reasons, a majority that was happy to leave a Supreme Court chair vacant for most of 2016. As we have said repeatedly, the Senate still has not been given access to all relevant documents, let alone fully checked out Ms. Ford’s allegation.

It would be irresponsible for Republicans to insist on an immediate vote. If they do, the responsible vote must be no.