DURING HIS first presidential debate against Hillary Clinton, Donald Trump congratulated himself on his restraint in not bringing up the sexual behavior of Bill Clinton. “Inappropriate . . . not nice” was his explanation of why “I just can’t do it.” But any vestige of nicety evaporated when the lewd video of Mr. Trump boasting about the sexual assault of women surfaced. Since Sunday’s second debate, Mr. Trump has placed at the center of his campaign women who have accused Mr. Clinton of sexual improprieties, while charging Ms. Clinton with “viciously” attacking women. It’s a dodge that voters should reject.

That Mr. Trump thinks he can whitewash his vulgar treatment of women by revisiting Mr. Clinton’s misdeeds is yet another example of the morally bankrupt campaign he is waging. Mr. Clinton behaved disgracefully when he had sexual relations with a White House intern and lied about it. But it is Ms. Clinton, not her husband, who is running for president. Blaming Ms. Clinton for her husband’s misconduct is as ludicrous as holding Melania Trump — or the two wives who preceded her — responsible for Mr. Trump’s inappropriate comments and actions.

Mr. Trump’s other line of attack — that Ms. Clinton enabled and covered up her husband’s sexual misconduct by attacking the women who made accusations — might be a legitimate issue for voters. But the record is murky and the evidence scant. “The claim that Hillary Clinton worked to silence Bill Clinton’s accusers largely rests on assumptions that are in dispute” was the assessment of a Post fact check posted the night of the second debate.

Ms. Clinton said unkind words about a woman who sold her story about having an affair with Mr. Clinton as he campaigned for president in 1992; she privately confided her thoughts about Monica Lewinsky to a friend; and she argued — not without justification — there were political motivations behind some of the attacks. But the extent, if any, of her involvement in active campaigns to discredit accusers is unclear. One particularly pernicious allegation — of threatening a woman who claimed to have been raped by Mr. Clinton (who was never charged and has denied the allegation) — is based on the flimsiest of assertions. Equally unfair is Mr. Trump’s criticism of Ms. Clinton for her representation decades ago of a man accused of raping a 12-year-old girl. Ms. Clinton had not wanted to represent the man but she had been appointed by the court and — unlike Mr. Trump — understood that the American system of justice is founded on the constitutional right of the accused to proper representation.

Any assessment of Ms. Clinton’s actions with regard to her husband should not lose sight of the painful dilemmas inherent in confronting the infidelities of a spouse. As one writer observed in the Atlantic, “Asking someone to react rationally and sympathetically to a person having an affair with their spouse is to demand superhuman self-control and circumspection.” Ms. Clinton’s desire to believe her husband was not out of bounds. What is out of bounds is Mr. Trump’s cynical use of women who say they were abused as cover for his own abominable behavior.