WASHINGTON — John Bolton, the former national security adviser to President Donald Trump, said Monday he is willing to testify in the Senate impeachment trial if subpoenaed.

In a statement posted Monday, Bolton wrote, "I have concluded that, if the Senate issues a subpoena for my testimony, I am prepared to testify."

The decision marks a significant, and potentially dramatic, development in the impeachment process that House Democrats set in motion just two weeks after Bolton left the White House on contentious terms with the president. It’s also a reversal for Bolton, who previously said he would only testify before Congress if he is subpoenaed and a judge ordered him to defy the White House by appearing.

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Bolton had a front-row seat to the White House’s pressure campaign against Ukraine to investigate the son of Trump’s political rival, former Vice President Joe Biden, including the decision to withhold military aid. He served as Trump’s national security adviser for more than a year, until his departure in September.

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Democrats quickly sought to use Bolton’s decision to put pressure on the small group of moderate Senate Republicans who are facing tough re-election fights in November.

“It is now up to four Senate Republicans to support bringing in Mr. Bolton, and the other three witnesses, as well as the key documents we have requested to ensure all the evidence is presented at the onset of a Senate trial," Senate Minority Leader Chuck Schumer, D-N.Y., said. “Given that Mr. Bolton’s lawyers have stated he has new relevant information to share, if any Senate Republican opposes issuing subpoenas to the four witnesses and documents we have requested, they would make absolutely clear they are participating in a cover-up.”

Bolton is an important witness to misconduct involving Ukraine that he called a “drug deal.”



Bolton refused to testify in the House, following Trump’s orders.



Now he is willing to come forward. The Senate must allow testimony from him, Mulvaney and others. The coverup must end. https://t.co/3JCaw8W8y3 — Adam Schiff (@RepAdamSchiff) January 6, 2020

It remains to be seen whether Senate Majority Leader Mitch McConnell, R-Ky., will subpoena Bolton. Congressional leaders remain deadlocked over the parameters of how the trial would be conducted. One of the primary divisions is over Democratic calls to include new witnesses, such as Bolton, and his willingness to testify is likely to put new pressure on Senate Republican leaders to allow witness testimony.

Bolton called McConnell on Monday to inform him of his decision before his statement went public, according to a source with first-hand knowledge, but he didn’t reach him and left a message.

House Speaker Nancy Pelosi, D-Calif., has not yet sent the articles of impeachment the House approved last month to the Senate. The Senate would only need a simple majority — or 51 votes — to call a witness.

McConnell has said he’s coordinating closely with the White House on the rules of the Senate trial.

The White House had no immediate official reaction. A senior administration official, however, downplayed concerns about Bolton testifying. “Bolton could say he disagrees with the president, but that’s not an impeachable offense,” the official said. A White House official also said any testimony from Bolton would not amount to additional evidence gathering on the Ukraine matter, noting that has concluded with the House vote.

“Bolton’s statement doesn’t change the Senate’s role in ruling on the evidence provided by the House,” the White House official said.

Pelosi called on Trump and McConnell to allow witnesses to testify “so Americans can see the facts for themselves.”

A senior Democratic congressional aide credited Pelosi’s strategy of withholding the impeachment articles from the Senate for compelling Bolton’s change of view. “We would not have this development absent the speaker’s hold,” the aide said.

The President & Sen. McConnell have run out of excuses. They must allow key witnesses to testify, and produce the documents Trump has blocked, so Americans can see the facts for themselves.



The Senate cannot be complicit in the President's cover-up. #DefendOurDemocracy https://t.co/TQLJsfn0f5 — Nancy Pelosi (@SpeakerPelosi) January 6, 2020

The House declined to subpoena Bolton because he had said he would only testify under a court order, which Democrats said would have dragged out their investigation. But Bolton said in his statement that "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."

Bolton’s lawyer has said that the former national security adviser has information about the Ukraine issue that had not been disclosed publicly or to the House Intelligence Committee during its impeachment investigation.