Former national security adviser John Bolton said Monday that he is willing to testify before the Senate in President Donald Trump s impeachment trial if he is subpoenaed.

I have concluded that, if the Senate issues a subpoena for my testimony, I am prepared to testify, Bolton said in a statement .

Boltons agreement to testify if subpoenaed, however, doesnt necessarily mean the Senate will actually hear from him.

Senate Majority Leader Mitch McConnell (R-Ky.) and Minority Leader Chuck Schumer (D-N.Y.) are currently trying to work out an agreement on what the rules will be for an impeachment trial.

The Democratic position is that calling witnesses is essential to a fair process, and Schumer has specifically requested the testimony of four people who did not testify before the House including Bolton. But McConnell hasnt agreed to subpoenaing witnesses or additional documents that shed light on the Ukraine scandal and what role Trump specifically played in pressuring the country to investigate former Vice President Joe Biden and his family.

House Democrats decided not to subpoena Bolton while the chamber mulled over whether to draft impeachment articles last year. They reached the decision after the White House declared it wouldnt cooperate with the hearings and instructed top officials whod already been subpoenaed not to comply.

As a result, numerous top officials familiar with Trumps thinking including acting White House chief of staff Mick Mulvaney, White House attorney and legal adviser to the National Security Council John Eisenberg, and former Energy Secretary Rick Perry have remained silent.

House Speaker Nancy Pelosi (D-Calif.) has so far refused to send the articles of impeachment to the Senate, meaning McConnell has not been able to start the trial.

If Bolton genuinely wants to all the information he has about Trumps conduct, there are ways he could do so without waiting for a subpoena, such as talking to Congress voluntarily or even giving an interview to the press.