Why was Kavanaugh evasive?

In the end, it came down to one simple, yes-or-no question to Judge Brett Kavanaugh from Senator Dick Durbin — would Mr. Kavanaugh support a request to have the FBI interview his witnesses, primarily Mark Judge, his very close friend in high school?

Mark Judge could fully and completely absolve Brett Kavanaugh of any hint of wrongdoing by testifying under oath to Mr. Kavanaugh’s character and behavior in those days. Mark Judge could plainly attest to the truth of all that Mr. Kavanaugh has said. Mr. Judge’s testimony would strongly support the image of Mr. Kavanaugh as a solid, decent, sincere, hardworking young man. Sure, they’d occasionally had a few beers together and, maybe, on rare occasions, a couple too many, but basically, Mr. Judge’s testimony could abolish the cloud that sits over Mr. Kavanaugh’s head. Simultaneously, Mr. Judge’s testimony could cast serious doubt on Christine Blasey Ford’s recollection, since Ms. Ford so clearly says she remembers Mark Judge’s being in the room during the alleged assault. Finally, Mr. Judge’s testimony could provide the wavering U.S. senators the assurance they’re looking for to go ahead with his confirmation.

If Mr. Kavanaugh is telling the truth, there is no conceivable reason why he would not want to have such powerful eyewitness testimony in his favor. Yet though he was asked repeatedly to offer his support for an FBI investigation, Mr. Kavanaugh refused to answer: he was evasive, flustered and hostile. His extremely aggressive and rude behavior toward those who have the power to make or break his nomination is impossible to understand. If he’s telling the truth.