WASHINGTON, Jan. 6 (Xinhua) -- A Senate trial of U.S. President Donald Trump's impeachment is still in limbo as Republicans and Democrats remain locked in an impasse over its rules while former National Security Advisor John Bolton's offer to testify on Monday made the standoff more awkward.
Trump was impeached by the Democrat-led House last month for abuse of power and obstruction of Congress. But the articles of impeachment haven't been delivered to the Republican-controlled Senate, which has thrown the trial into uncertainty.
House Speaker Nancy Pelosi, who initiated an inquiry in September 2019 that led to Trump's impeachment, has tried to give Democrats more leverage in negotiations with Republicans for setting rules for the trial.
Senate Minority Leader Chuck Schumer had proposed hearings from several witnesses, including Bolton and acting White House Chief of Staff Mick Mulvaney, during the Senate trial, while the Majority Leader Mitch McConnell has rejected the demand.
Bolton's announcement on Monday that he's willing to testify in the impeachment trial if subpoenaed added heat to the standoff.
"I have concluded that, if the Senate issues a subpoena for my testimony, I am prepared to testify," said Bolton, who left the White House before the start of the impeachment inquiry, in a statement.
Bolton also said he has weighed the issues of executive privilege and that after "careful consideration and study" he has decided that he would comply with a Senate subpoena.
Pelosi seized upon Bolton's statement, urging Republicans to agree to Schumer's proposal.
"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 California Democrat tweeted. "The Senate cannot be complicit in the President's cover-up."
Chairman of the House Intelligence Committee Adam Schiff, who led the House's impeachment inquiry into Trump, called Bolton "an important witness," who refused to voluntarily provide testimony before impeachment investigators.
"Now he is willing to come forward. The Senate must allow testimony from him, Mulvaney and others. The cover-up must end."
A 51-vote majority will be required from the Senate in order to obtain the subpoena for Bolton to testify. Currently, the Senate has 53 Republicans, 45 Democrats and two independents.
McConnell didn't weigh in on Bolton's offer on Monday. Instead, he said the Senate should follow the "precedent" of then-President Bill Clinton's 1999 impeachment trial.
McConnell has previously said he wants to pass two resolutions, one at the outset of the trial about the rules, and the other passed after opening arguments and questions from senators, which would determine who will be called as witnesses, similar to the Clinton trial.
"The Senate has a unanimous bipartisan precedent for when to handle mid-trial questions such as witnesses - in the middle of the trial," McConnell said on Monday. "That was good enough for President Clinton, so it ought to be good enough for President Trump. Fair is fair."
Trump, who has denied any wrongdoing, on Monday slammed his impeachment case as a "hoax" and "witch hunt."
"The Impeachment Hoax, just a continuation of the Witch Hunt which started even before I won the Election, must end quickly," he tweeted. "It is a con game by the Dems to help with the Election!"
In an anonymous complaint last summer, a whistleblower raised concerns about the White House's interactions with Ukraine, including a phone call between Trump and his Ukrainian counterpart, Volodymyr Zelensky.
Trump was alleged to have pressed Zelensky into launching investigations that could politically benefit him. Furthermore, the White House allegedly tried to cover it up.
Laurence Tribe, professor of constitutional law at Harvard University, said on Monday that it won't be easy for Bolton to produce testimony in the Senate trial of Trump's impeachment.
"What makes anyone think Trump won't run to court to get an injunction against Bolton, claiming executive privilege and national security, if Bolton receives a subpoena?" Tribe tweeted. "Any competent court would rule against Trump, but Trump would appeal. That litigation could last until Fall."