Before Bill O’Reilly’s ouster from Fox News, his attorney claimed O’Reilly was the target of a left-wing “smear campaign” and that they possessed “irrefutable proof.”

Part of that proof (potentially) was an email O’Reilly’s team had obtained from Mary Pat Bonner, a Democratic fundraiser, about an “advertiser education campaign” targeting O’Reilly, and announcing conference calls with Media Matters President Angelo Carusone on April 20 and 21. As of Tuesday night, O’Reilly was discussing whether to show the email to Fox with his attorneys.

“If we show to Fox tomorrow, word will get out and the Thursday call may be cancelled,” O’Reilly wrote in an April 18 email exchange that was forwarded to POLITICO on Wednesday night by a member of O’Reilly’s legal team at Kasowitz, Benson, Torres & Friedman, but which a representative for O’Reilly subsequently said had been sent by mistake.

“So no formal sending to Rupert until after the call,” O’Reilly continued, before venting: “You all should know that I will not put up with much more from FNC.”

Whoops. If that’s the only email that was inadvertently (?) shared with Politico by O’Reilly’s legal team, he’s got to be breathing a sigh of relief.

The “campaign” against O’Reilly was hardly secret, though. Carusone spoke about it earlier this month in a separate Politico feature.