Sen. Kamala Harris, D-Calif., was lauded for a mysterious set of questions she asked to Judge Brett Kavanaugh during his Supreme Court hearing on Wednesday. Specifically, she asked whether he had spoken to anyone at a particular law firm — Kasowitz Benson Torres — about Robert Mueller's special counsel investigation.

President Trump has repeatedly hired this firm, it turns out, for representation in various matters both before and during his presidency. And one of its principals, Marc Kasowitz, is representing him right now in that very investigation into Russian interference in the 2016 election.

In response to Harris' question, Kavanaugh expressed puzzlement. He didn't seem to know much about the firm or who is in it. But noticing the certainty with which she made her assertions, he admitted it was possible he could unknowingly have an acquaintance there. So he was hesitant to give a categorical answer right away.

In the moment on Wednesday, Harris curtly chalked up his uncertainty as if it implied he was hiding something. She did that again in interviews with the press. Her tone was that of an unethical prosecutor trying to prejudice a jury — which is to say, this is Harris' area of professional expertise.

Afterward, the firm's principal and Trump's personal attorney, Kasowitz, publicly denied that anyone at the firm had spoken to Kavanaugh. But Harris, acting perhaps from a desperate need to one-up 2020 presidential rival Sen. Cory Booker, D-N.J., continued to insinuate in press interviews that she had evidence that some kind of conversation about Mueller had indeed occurred. “I have good reason to believe there was a conversation,” Harris told reporters Thursday morning. “Information that I’ve received is reliable and I asked him a clear question and he couldn’t give a clear answer.”

Harris has since been forced to walk back her embarrassing and apparently slanderous assertion that Kavanaugh — a federal judge who in his current role might well end up hearing one or more Mueller-related cases even if he isn't confirmed to the Supreme Court — went out of his way to discuss the investigation with Trump's defense attorneys.

But hey, why shouldn't Harris make such claims? This is the very sort of unprofessional behavior that lousy prosecutors who put self-advancement ahead of truth get away with routinely. In short, the former California official who " repeatedly attempted to keep an innocent man locked up in prison and attempted to defend a falsified confession," in addition to defending her subordinate prosecutors' lies on the witness stand, isn't going to have qualms about claiming that a conversation took place without really knowing whether it did. Just throw it all against the wall and see what sticks.

The mystery of where Harris came up with her question was solved later on. It turned out that Kavanaugh does actually know someone at Kasowitz — Edward McNally, whom he had worked with many years ago in the Bush administration. On Thursday, after having a chance to study the firm's roster, Kavanaugh was able to testify under oath that he definitely had not discussed the Mueller investigation with McNally or anyone else at the firm.

At this, Harris folded her hand instantly, declaring bitterly that Kavanaugh could have put the matter to rest with a clear answer on Wednesday. And the speed with which she did so was very telling. Harris had been on a fishing expedition. She had pretended to have a big one on the line. What she might not have realized is that although such a bluff might work in getting some nervous half-wit to plead guilty to something he didn't do, it isn't going to derail a Supreme Court nominee who knows the confirmation process about as well as any living human being. This isn't a police station interrogation room — here, you have to reel that fish in before you can brag about catching it.

After this incident, any journalist on Capitol Hill who believes anything Harris says without documentary evidence should have his or her head examined. It's very common for senators to stretch the truth about almost any topic, but it's exceedingly rare for them to just make things up that are so easily debunked. Most of them are bright enough to realize that's just too stupid and risky.

Speaking of which, if you want to know who probably does know the members of Kasowitz Benson Torres, it's Harris. She was the Senate's third highest recipient of that firm's campaign cash during the 2016 election cycle, the one in which she was elected.

Harris took $5,070 from the firm's employees, putting her behind only Chuck Schumer ($16,800) and Marco Rubio ($26,850) for that period. Incidentally, the firm's top recipient overall that year was Hillary Clinton ($34,688), who got more than twice as much as the firm's longstanding client Donald Trump ($16,200).

This year, Kasowitz Benson Torres employees are putting their big money ($22,900 as of July 1) on Sen. Bob Menendez, D-N.J., who beat bribery charges last November thanks to a hung jury.

Did Harris speak to any of the Kasowitz Benson Torres attorneys who donated money to her campaign? If she doesn't answer immediately then it's probably a sign that she's guilty of something.