Former Fox News host Bill O'Reilly, who has repeatedly been accused of sexual harassment. (Frank Micelotta/Invsion/AP)

Bill O'Reilly is trying to discredit Megyn Kelly and Gretchen Carlson by publicizing friendly, handwritten letters they sent to him at unspecified dates in the past. His contention is that former colleagues' public criticisms should be viewed as posturing and piling on because they do not match the sentiments expressed when no one was watching.

O'Reilly is playing with fire here. By going after Kelly and Carlson, he is tempting them to reveal information they might otherwise keep to themselves.

That's how we got to this point. Carlson is an advocate for targets of sexual harassment, but it is clear that she would rather not — actually, cannot — rehash everything that happened at Fox News.

“I can't talk about that,” she replied last week when The Washington Post's Kathleen Parker asked about the level of support Carlson received at Fox News after alleging sexual harassment by then-chairman Roger Ailes in a lawsuit last year. “I can't talk about specifics about my time at Fox,” she added in a recent interview with Slate. Carlson settled her case for $20 million; settlements often impose restrictions on future disclosures.

Carlson can drop hints, however, and she appeared to do just that over the weekend, when O'Reilly responded defiantly to a New York Times report that he paid $32 million to settle a sexual harassment claim in January 2016.

The wording of Carlson's tweet was generic, but the message carried the weight of someone with inside knowledge of the situation who overlapped for a decade at Fox News with O'Reilly and his accuser, attorney Lis Wiehl.

Although Carlson generally avoids discussing Fox News these days, she felt compelled to weigh in on O'Reilly's latest denial.

Similarly, Kelly was moved to speak out after O'Reilly's attorney issued a statement that claimed that “in the more than 20 years Bill O'Reilly worked at Fox News, not one complaint was filed against him with the human resources department or legal department by a co-worker, even on the anonymous hotline.”

“O'Reilly's suggestion that no one ever complained about his behavior is false,” Kelly asserted Monday on her NBC morning show. “I know because I complained.”

Kelly went on to share an excerpt of a previously unpublicized email she sent to Fox News executives in November 2016. In the email, she referenced O'Reilly's “history of harassment of women, which has, as you both know, resulted in payouts to more than one woman, including recently.”

“It gives me no pleasure to report such news about my former employer,” Kelly told her viewers. Yet she is reporting it now, as a direct result of O'Reilly's claim that “not one complaint was filed.”

O'Reilly is making things worse for himself by antagonizing Kelly and Carlson. Despite loud promises of exoneration, he has little to show for a six-month effort to clear his name. He seems to believe the letters he posted online Monday will help his case, but they hardly invalidate what Kelly and Carlson are saying now.

One letter from Kelly is a baby gift thank-you note. Kelly had her three children between 2009 and 2013. A second letter thanks O'Reilly for promoting a novel authored by Kelly's husband, Douglas Brunt. Fox News transcripts show that O'Reilly plugged Brunt's “Ghosts of Manhattan” on Oct. 18, 2012.

The dates indicate that several years passed between Kelly's notes to O'Reilly and her complaint to network executives. That is plenty of time for Kelly's opinion of O'Reilly to sour.

The single letter from Carlson that O'Reilly posted includes no date markers. But there is nothing contradictory about what Carlson wrote in the past and what she is saying now. In the letter, Carlson thanked O'Reilly for “supporting me” and “for being my friend.”

It is possible O'Reilly was a good friend to Carlson at the same time that he allegedly harassed other women; the two behaviors would not be mutually exclusive. And Carlson's prior friendship with O'Reilly does not preclude her from condemning him today.

If O'Reilly wants Kelly, Carlson and others to stop talking about him, provoking them this way may not be the best strategy.

The Washington Post's Margaret Sullivan discusses how sexual harassment allegations at Fox News are changing workplace culture. (The Washington Post)