Christine Ford has made disturbing allegations of attempted sexual assault against Supreme Court nominee Brett Kavanaugh. While they are serious and while they should be investigated, that does nothing to change the fact that Senate Democrats have no credibility on the issue.

The same Sen. Dianne Feinstein, who now demands an excruciating investigation of the Ford allegations, didn’t bat an eye when a sitting president was credibly accused of rape.

Feinstein, along with Dick Durbin of Illinois, Chuck Schumer of New York, and Patty Murray of Washington were in Congress when Juanita Broaddrick accused then President Bill Clinton of raping her (Clinton was not a teenager at the time) in his hotel room during his first gubernatorial race in Arkansas in 1978. The Senate was in the middle of an impeachment trial in 1999 and not one of those Democrats called for an investigation into the Broaddrick accusations.

This does not mean that Ford should now be dismissed out of hand. But it indicates Senate Democrats' opportunism.

[More: The long silences of Christine Blasey Ford and Dianne Feinstein]

Feinstein and company knew of the Broaddrick allegations. She had been interviewed by independent counsel Kenneth Starr's office and some of the details had leaked publicly. They could read allegations that Clinton lured Broaddrick to his hotel room by switching the location of a meeting at the last moment, that she resisted and he persisted pushing her onto the bed, that the forcible sex left her shaken and bruised. Either they ignored it, or worse, never even bothered to examine the evidence.

Others found the material more than convincing. According to the New York Times, “a dozen or so representatives” actually reviewed the testimony Broaddrick gave to Starr. “In some cases,” the Times then reported, “reading the Broaddrick files ended the representatives' qualms and made them feel at peace with their decisions to support impeachment.”

It didn’t rile Feinstein or any of the other Democrats in the Senate.

They didn’t interview Broaddrick, let alone any of her friends—Louise Ma, Susan Lewis, and Jean Darden—who told NBC News that Broaddrick had told them “that she had been raped by Bill Clinton.”

They didn’t ask for Norma Rogers to take a polygraph to corroborate how she found Broaddrick laying in the hotel room with a bruised upper lip, “crying and in 'a state of shock.’”

They didn’t do anything back then.

Of course, the Senate should have done something. Broaddrick was a credible accuser and Clinton a habitual womanizer. Starr had found the allegations serious. So did those dozen members of the House of Representatives. The information merited additional scrutiny and Broaddrick deserved a day in court—one that she never got. Nineteen years ago, Feinstein and company ignored the allegations and voted “not guilty.”

When viewed side by side, the reactions to the Ford and the Broaddrick allegations paint an ugly picture of Feinstein’s opportunism. She sat on this information, waiting until the last possible moment to maximize chances of sinking Kavanaugh. She ignored similar information to in order to save Clinton.

The same mistake cannot be made now. Ford deserves to have her allegations heard by senators today. But Feinstein does not deserve to be treated as credible.