Bolton’s attorney Chuck Cooper said late Oct. 30 that Bolton will not appear without a subpoena.
Democrats have issued subpoenas to several other witnesses who ended up testifying.
Lawmakers want to hear from Bolton after other witnesses told them of his concerns with Trump’s dealings in Ukraine and the backchannel activities of Rudy Giuliani, Trump’s personal lawyer.
Trump asked Ukrainian President Volodymyr Zelensky in a July phone call to look into CrowdStrike, a company hired by the Democratic National Committee to investigate a network breach, and also into former Vice President Joe Biden and Biden’s son, Hunter Biden.
Biden said last year that in 2016 he threatened to withhold $1 billion in aid from Ukraine unless then-President Petro Poroshenko ousted Viktor Shokin, a prosecutor who was probing Burisma.
Hunter Biden was on the board of Burisma from 2014 to 2019.
Some Democrats have claimed Trump asked Zelensky to investigate a political rival because Biden is running for the Democratic presidential nomination to challenge Trump.
House Democrats wanted Bolton to testify on Nov. 7.
Another potential witness, former deputy national security advisor Charles Kupperman, didn’t appear on his scheduled date after he filed a lawsuit asking a judge whether he should follow the argument by Trump’s White House that he shouldn’t cooperate due to executive privilege, or whether he should appear and testify about what he knows.
“Plaintiff is faced with irreconcilable commands by the Legislative and Executive Branches of the Government and, accordingly, seeks a declaratory judgment from this Court as to whether he is lawfully obliged to comply with a subpoena issued by the House Defendants demanding his testimony ‘pursuant to the House of Representatives’ impeachment inquiry,’ or he is lawfully obliged to abide by the assertion of immunity from congressional process made by the President in connection with the testimony sought from Plaintiff,” the lawsuit stated.
Kupperman was an aide to Bolton while both were working for the Trump administration.
House Democrats threatened to hold Kupperman in contempt when he didn’t appear to give testimony.
House Intelligence, Oversight, and Foreign Affairs committees will “obviously consider, as we inform Dr. Kupperman’s counsel, his failure to appear as evidence that may warrant a contempt proceeding against him,” House Intelligence Chairman Adam Schiff (D-Calif.) told reporters.
On Thursday, former Trump adviser Tim Morrison arrived on Capitol Hill to testify to House investigators.
Morrison, who served on the National Security Council, stepped down from that post on Wednesday, and a senior administration official said he “decided to pursue other opportunities.” The official, who was not authorized to discuss Morrison’s job and spoke only on the condition of anonymity, said Morrison had been considering leaving the administration for “some time.”
Morrison will be asked to explain that “sinking feeling” he got when Trump asked Ukraine’s president investigate former Vice President Joe Biden and interference in the 2016 election.
The national security hawk, brought on board by then-national security adviser Bolton, has been featured prominently in previous testimony from diplomat William Taylor in the impeachment inquiry. It was Morrison who first alerted Taylor of concerns over Trump’s phone call with Zelensky that the security adviser relayed “could have been better.”
The Associated Press contributed to this report.