'He's done with Trump': John Bolton watchers explain why 'weird' ex-adviser is now willing to testify
John Bolton appears on CBS (screen grab)

Former National Security adviser John Bolton announced on Monday that he would testify before the Senate in the trial of President Donald Trump if he is asked.

Bolton made the remarks in a statement on his website.

National security experts quickly weighed in on Twitter with explanations and ideas about why Bolton had waited until now to say he would comply with a Senate subpoena.

Read some of the tweets below.