Not sure why he’s doing this now. I gather his relationship with President Trump is irrevocably broken, and he hopes to do what he can to ensure a President Pence – who after all is an Iran hawk, like Bolton.
Pence was among the Trump aides who backed killing Qassem Soleimani.
But who knows?
From a statement by Bolton:
The House has concluded its Constitutional responsibility by adopting Articles of Impeachment related to the Ukraine matter. It now falls to the Senate to fulfill its Constitutional obligation to try impeachments, and it does not appear possible that a final judicial resolution of the still-unanswered Constitutional questions can be obtained before the Senate acts.
Accordingly, since my testimony is once again at issue, I have had to resolve the serious competing issues as best I could, based on careful consideration and study. I have concluded that, if the Senate issues a subpoena for my testimony, I am prepared to testify.