Democrats’ desperate drive to derail the Brett Kavanaugh nomination just took a despicable new turn with a last-minute push to exploit an anonymous allegation that Sen. Dianne Feinstein’s been sitting on for months.

With Kavanaugh poised to win confirmation with up to 55 votes, Judiciary Committee Dems late Wednesday plainly held a final does-anyone-have-anything? session. DiFi mentioned a confidential letter she’d received over the summer — and by the next day the partisans had made the core facts public.

In the letter, originally sent to Rep. Anna Eshoo (D-Calif.), a woman allegedly claims she was the victim of some Kavanaugh “sexual misconduct” … back in high school.

As Feinstein explains, “That individual strongly requested confidentiality, declined to come forward or press the matter further, and I have honored that decision.”

Except that, after the Wednesday meeting, she did other Dems’ bidding by passing the letter on to “federal investigative authorities.” And some Democrat(s) quickly clued in the media.

It’s an extremely safe bet that political operatives are now pressuring the woman to go public — against her express wishes. That, after all, is what Democrats did to Anita Hill a quarter-century ago.

Absent that, no investigator can do a thing — the allegation runs back at least 35 years, to when Kavanaugh was a teenager. Which is surely why Feinstein did nothing in the months after she got the letter.

The honorable thing would’ve been to respect the woman’s wishes and keep quiet, rather than feed her to the partisan wolves.

As for the Democrats who pushed Feinstein into breaking that confidence, and then anonymously fed the “news” to the press: Congratulations, you just sank to a new low.