It’s rare that American history provides as neat a precedent as the confirmation process for Justice Clarence Thomas provides for the nomination of Brett M. Kavanaugh to join him on the Supreme Court. It’s not a perfect precedent, of course, but both in broad strokes and in specific areas, the allegations made by Anita Hill against Thomas mirror the accusations Christine Blasey Ford made against Kavanaugh.

The question of the moment is how to evaluate Ford’s allegations. We’ve moved beyond “he said, she said” territory, but it’s still the case that observers are left largely to their own evaluations of the veracity of the accuser and the accused.

On Tuesday evening, Lisa Banks, an attorney for Ford, indicated that her client did not plan to appear before the Senate Judiciary Committee at a hearing, scheduled for Monday, until there had been an independent investigation to evaluate her claims and Kavanaugh’s denial. In short order, the committee’s chairman, Sen. Charles E. Grassley (R-Iowa), seemed to rule that out.

“Nothing the FBI or any other investigator does would have any bearing on what Dr. Ford tells the committee, so there is no reason for any further delay,” he said.

Sen. Orrin G. Hatch (R-Utah), his colleague on the committee, went further. “The FBI does not do investigations like this,” a tweet from his office read. “The responsibility falls to us.”

That's not really true, as the example from the Thomas-Hill hearings makes clear.

The Kavanaugh allegation was first presented to Sen. Dianne Feinstein (D-Calif.) in a July letter, with a request that Ford’s identity be kept private. That limited how Feinstein was able to use the information, but she eventually turned it over to the FBI. In a statement, the Justice Department indicated that, in accordance with policy, it forwarded the letter to the White House Counsel’s Office but didn’t open an investigation because it didn’t deal with a federal crime. It’s worth noting that the White House counsel is Donald McGahn, who has played a lead role in shepherding Kavanaugh’s nomination through the Senate process.

President Trump was asked Tuesday whether he thought the FBI should be involved.

“I don’t think the FBI should be involved because they don’t want to be involved, if they wanted to be I would certainly do that,” Trump said. “As you say, this is not really their thing. The senators will do a good job.”

But Chris Strohm of Bloomberg News, citing someone familiar with the matter, reported that the FBI hadn’t said it didn’t want to be involved in evaluating the Ford accusations.

In 1991, when Hill’s allegations were made public, the FBI became involved at the direction of the White House.

“On Sept. 23, the allegation was brought to the attention of the Judiciary Committee,” a White House statement at the time read. “The Judiciary Committee immediately informed the White House. In consultation with the committee, the White House promptly directed the FBI to conduct a full, thorough and expeditious investigation. Upon completion of the FBI investigation on Sept. 26, the report was submitted to the White House and the committee.”

Note that the investigation lasted only three days, as CNN’s Kevin Liptak points out.

The White House of George H.W. Bush determined that Hill’s allegation was unfounded. It was only after that point that the allegation became public. In his testimony during the subsequent hearings on the issue, Thomas said that it was when the FBI raised the issue on Sept. 25 that he first learned of Hill’s allegations.

At the time of his alleged interactions with Hill, Thomas was a federal employee, which some have argued gives the FBI jurisdiction that it lacks in the Kavanaugh case. The FBI does have an established role in vetting federal nominees, though, predicated on unearthing information that might inform whether a candidate was a security risk. That process generally doesn’t extend back multiple decades to a candidate’s youth, former FBI agent Asha Rangappa indicated on Twitter, but it’s not at all clear that it couldn’t.

NBC’s Pete Williams reports that it “has always been the practice” for the FBI to wait for a request from the White House to investigate “derogatory” information revealed about a nominee of the president.

It’s also worth noting that, in an interview with CNN’s Anderson Cooper on Tuesday, Ford’s attorney indicated indifference about who carried out the investigation.

"Now, the Senate does have investigators,” Cooper noted. “It doesn't necessarily have to be the FBI. Would that be acceptable to you?"

“They have to be investigated,” Banks replied. “And, again, those are things we can discuss with Senator Grassley. Whether it’s the FBI or other investigators, it should be impartial investigators who are nonpartisan.”

Where would investigators start? Interviews with the principals, certainly, including Kavanaugh, Ford and Mark Judge, a conservative commentator who Ford says was in the room during the alleged incident. An attorney for Judge wrote a letter indicating that Judge didn’t intend to testify.

There is the therapist to whom Ford says she revealed the alleged incident several years ago. There’s the individual who says Ford told her about the alleged incident in vague detail over Facebook last year.

And there’s Patrick Smyth, who Ford alleges was also at the party where the incident is alleged to have occurred and who, through a letter from an attorney, denied the claim.

The advantage of an interview by federal authorities as opposed to letters from lawyers or interviews with the media is that a federal investigation would carry the weight of criminal charges in the event of deliberate falsehoods. That’s the possible rationale for Ford: She could testify before the Senate Judiciary Committee under oath knowing that those she alleges were involved in or knew about the allegations had to tell the truth under penalty of law.

Again: This is not unprecedented. The three-day investigation of Thomas may not have fully explored what Hill alleges took place, but it nonetheless occurred, with the White House’s blessing.

Trump seems unlikely to offer his own.