WASHINGTON >> President Donald Trump today bluntly questioned the allegation that Supreme Court nominee Brett Kavanaugh sexually assaulted a fellow high school student over 30 years ago, and Republicans warned the accuser that the window was closing to tell her story before a confirmation vote.

Trump’s skepticism, the most explicit challenge top Republicans have so far mounted to Christine Blasey Ford’s credibility, came as GOP Senate leaders tried to firm up support for Kavanaugh. A potentially climactic Judiciary Committee showdown is scheduled for Monday with both Ford and Kavanaugh invited, but her attendance is uncertain, casting doubt on whether the hearing will be held at all.

Ford has said she wants the FBI to investigate her allegation before she will testify. Democrats support that, but Trump and Senate Republicans have been emphatic that it won’t happen.

Leaving the White House to survey flood damage in North Carolina from Hurricane Florence, Trump conceded that “we’ll have to make a decision” if Ford’s account proves convincing. Despite that glimmer of hesitancy, which few other Republicans have shown publicly, the president stood firmly behind the 53-year-old Kavanaugh, who would fill the second high court vacancy of Trump’s term.

“I can only say this: He is such an outstanding man. Very hard for me to imagine that anything happened,” Trump said.

The Republicans are resisting all Democratic efforts to slow and perhaps block what once seemed a smooth path to confirmation that would promote the conservative appeals court judge by the Oct. 1 opening of the Supreme Court’s new term. Kavanaugh’s glide to approval was interrupted last weekend when word of Ford’s allegation became public, but GOP senators are showing no signs of slowing their drive to confirm him as quickly as possible.

Judiciary Committee Chairman Chuck Grassley, R-Iowa, wrote to Ford’s attorneys that the hearing was still scheduled for Monday morning, and he pointedly said she must submit her written statement by 10 a.m. Friday “if she intends to testify” that day.

Lisa Banks, a lawyer for Ford, released a statement late Wednesday that cast no light on whether her client will appear.

She wrote that Ford wants “a full non-partisan investigation” and said Ford is willing to cooperate. But she said Grassley’s plan to call just Kavanaugh and Ford “is not a fair or good faith investigation” and said “multiple witnesses” — whom she didn’t name — should appear.

“The rush to a hearing is unnecessary, and contrary to the Committee discovering the truth,” Banks wrote.

Ford has contended that at a house party in the 1980s, a drunken Kavanaugh tried undressing her and stifling her cries on a bed before she fled. Kavanaugh has repeatedly denied that claim.

Trump’s remark was noteworthy because most Republicans have handled the question of Ford’s credibility more gingerly. They say they want to give Ford, now a professor at Palo Alto University, every chance to tell her story.

“I’d really want to see her. I really would want to see what she has to say,” Trump said. “If she shows up that would be wonderful. If she doesn’t show up that would be unfortunate.”

Seven weeks from elections in which congressional control is at stake, Democrats have been unhesitant about casting Republicans as trying to strong-arm a victim of abuse.

The two parties’ tactics illustrate how they are trying to navigate a political climate in which the #MeToo movement of outing sexual abusers has galvanized many female voters. A substantial delay could push confirmation past the November elections, when Democrats have a shot at winning Senate control, plus allow more time for unforeseen problems to pop up.

“Dr. Blasey Ford is calling for an impartial FBI investigation of her serious and credible allegations. Meanwhile Republicans are trying to bully her into a rigged hearing before a neutral investigation and without the only identified eyewitness,” No. 2 Senate Democratic leader Dick Durbin of Illinois tweeted.

Ford and her Democratic allies also want the committee to interview Mark Judge, a Kavanaugh friend who Ford has said was in the bedroom during the attack. Judge has said he doesn’t remember the incident, never saw Kavanaugh act that way and has no desire to testify publicly.

There were signs the GOP’s strategy of planning a nationally televised hearing while also offering Ford the chance to testify in private was keeping possible Republican defections in check. The party controls the Senate 51-49 and the Judiciary panel by 11-10, so it cannot afford GOP “no” votes.

Moderate GOP Sen. Susan Collins of Maine, who’s had her share of clashes with Trump, said she hoped Ford would reconsider a decision not to testify and “it’s not fair to Judge Kavanaugh” if she refuses. “Otherwise, there are these very serious allegations hanging over the head of a nominee who has emphatically denied them,” she said on WVOM radio in Bangor.

Going further, Sen. Lindsey Graham, R-S.C., said Democrats’ demands for an FBI investigation were a ploy to delay a confirmation vote. “It is imperative the Judiciary Committee move forward on the Kavanaugh nomination and a committee vote be taken as soon as possible,” the committee member said in a statement.

As for a possible FBI intervention, Grassley said in his letter to Ford’s lawyers, “We have no power to commandeer an Executive Branch agency into conducting our due diligence.”

In a separate letter to Democrats, Grassley wrote that committee aides were “even willing to fly to California, or anywhere else, to meet her.” He also wrote that GOP aides tried to arrange interviews with two other “alleged witnesses.” The letter mentioned no names and committee staff declined to name them.

Only the White House can order the FBI to get involved, since Kavanaugh is not accused of a federal crime. The FBI could interview Ford, Kavanaugh and others about the allegation if Trump asked the bureau to reopen its background investigation, but the president has said the FBI has finished its work.

Kavanaugh did not return to the White House today after spending the two previous days there. He spoke by phone with officials working on strategy, according to an aide familiar with the proceedings but not authorized to speak publicly about private conversations.

The White House war room largely was centered on shaping the public perception of the nominee, pushing back on reporters’ inquiries while circulating positive talking points to allies about Kavanaugh.

Kavanaugh spent hours Tuesday in the Eisenhower Executive Office Building, part of the White House complex. He prepared for Monday’s potential hearing with officials including White House Counsel Don McGahn, press secretary Sarah Huckabee Sanders and communications director Bill Shine, as well as Justice Department aides.

Shine was ousted from his previous job at Fox News in part due to his handling of sexual harassment claims at the company.