It is unclear what information Bolton could provide and if it will help the Democrat's case against the President. It also remains unclear if Senator Mitch McConnell will allow Bolton to be subpoenaed.
Former national security adviser John Bolton said that he would testify if he is subpoenaed as part of the Senate’s impeachment trial of President Donald Trump.
In a statement posted online, Bolton, who was asked to testify as part of the House's impeachment inquiry but did not, said he wants to meet his “obligations” both as a citizen and as a former top presidential adviser.
“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,” Bolton wrote. “I have concluded that, if the Senate issues a subpoena for my testimony, I am prepared to testify.”