Inside Trumpworld, it is widely assumed Bolton is behind the leak, three Republican sources told me. Their suspicion is driven by the fact that Bolton left the administration in September on bad terms and has been waging a shadow war against Trump ever since. In November, NBC News reported Bolton trashed Trump during a private speech, saying Trump’s foreign policy was driven by Trump’s business interests. A source close to Bolton told me that Bolton has privately told GOP donors that Trump is “mentally unstable.” Bolton also has said he worries Trump will pull the United States out of NATO if he gets a second term. “Bolton’s been out there trying to bring down Trump. He’s the ultimate passive-aggressive,” the person close to Bolton said. (Bolton did not respond to a request for comment.) In early January, Bolton released a statement on his website declaring he was willing to testify at Trump’s trial.