John Bolton decides that he will testify in Senate impeachment trial if subpoenaed

John Bolton, former national security adviser to President Donald Trump, has decided he will testify in the Senate impeachment trial if he is subpoenaed.

"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," he said in a statement posted on his website Monday.

Why does this matter?

Rumors about Bolton's possible appearance as a witness before Congress have swirled for months following news that he allegedly possesses crucial knowledge regarding the Trump administration's dealings in Ukraine.

Democrats have sought for Bolton, along with White House chief of staff Mick Mulvaney, to appear as witnesses in the forthcoming Senate trial believing their testimony would be damaging to Trump. Democrats hope that Bolton's testimony would prove that Trump committed an impeachable offense in requesting that Ukraine launch investigations into the Bidens and Ukrainian natural gas company, Burisma, while withholding military aid from the country.

While Republicans have not to this point agreed on calling any witnesses, Bolton's decision to testify if subpoenaed undoubtedly adds pressure for them to do so. Still, the whole matter is at a stand-still at the moment while Speaker of the House Nancy Pelosi (D-Calif.) delays transferring the articles of impeachment to the Senate.

What's the background?

After his tumultuous exit from the White House, Bolton became a target witness for impeachment prosecutors due to his potential firsthand knowledge of the president's thoughts and actions.

During the House impeachment inquiry, he was invited to testify but did not attend his scheduled deposition and was not subsequently subpoenaed.

Bolton reportedly had major concerns regarding Trump attorney Rudy Giuliani's involvement in Ukraine.

Fiona Hill, the White House's former top Russia adviser, testified during closed-door testimony that Bolton was so concerned about the Ukraine intervention of Giuliani that he directed Hill to inform a White House lawyer about it.

According to Hill, Bolton called the intervention a "rogue operation" and a "drug deal" conducted by Giuliani, Mulvaney, and Gordon Sondland, the U.S. ambassador to the European Union.

"I am not part of whatever drug deal Sondland and Mulvaney are cooking up," Hill recounted Bolton saying. He then allegedly called Giuliani a "hand grenade who's going to blow everybody up."

In November, a lawyer for Bolton teased that his client has information about "many relevant meetings and conversations that have not yet been discussed" in the impeachment probe.

If Bolton were to appear before Congress for questioning, he would become the closest adviser to President Trump to testify in the impeachment proceedings.