Trump hits back at 'explosive' Bolton book leak as pressure builds on Republicans to call him as impeachment witness

Key GOP senators are mum as White House says Bolton is pushing false account to increase sales

Details of a new book by John Bolton likely will upend the Senate's impeachment trial of Donald Trump, pressuring a handful of Republicans to consider demanding his testimony as the White House paints him as pushing false claims to drive up sales.

Democratic senators and presidential candidates are saying the conservative hawk should be called as a witness in the trial after the New York Times on Sunday reported the president last year told Mr Bolton, whom Mr Trump fired in September over policy differences, he wanted to keep a $391m military aid package for Ukraine frozen until that country's government announced investigations into his US Democratic rivals, including Joe Biden and son Hunter Biden.

The Bolton revelation should alter the Senate's trial on removing Mr Trump "very dramatically", House Democrats' lead impeachment manager, Intelligence Committee Chairman Adam Schiff said on Monday morning.

"Our view is this is already overwhelming," Mr Schiff told CNN, saying Mr Bolton's testimony only further adds to testimony by other current and former Trump administration officials who told the House last year the aid package was directly tied to Mr Trump's desired investigations.

"This is the test of these senators," Mr Schiff said. "The question is: Do they want to hear the truth?"

To attempt calling Mr Bolton as a witness, Democrats need to hold their 47 votes in line and pick off four Republicans. The reported revelations in the book manuscript already is raising the temperature for moderate GOP senators Susan Collins of Maine, Lisa Murkowski of Alaska and Cory Gardner of Colorado. Also likely to receive calls to join Democrats in voting to bring in Mr Bolton during the trial are Tennessee senator Lamar Alexander and Utah senator Mitt Romney.

The manuscript contradicts Mr Trump's account of the aid freeze. He contends he held up the monies over concerns it would not be spent properly because of severe corruption inside the Ukrainian government. The book also reportedly will reveal that Secretary of State Mike Pompeo did not agree with the opinion of Trump surrogate Rudy Giuliani that helped lead Mr Trump to fire former American Ambassador to Ukraine, Marie Yovanovitch.

But Mr Trump and top aides are pushing back against Mr Bolton's account, with White House Press Secretary Stephanie Grisham saying on Monday morning the Trump team finds timing of the leaked details "very suspect" because the New York Times article coincides with the start of online pre-sales of the coming book. Her boss flatly denied Mr Bolton's account.

"I NEVER told John Bolton that the aid to Ukraine was tied to investigations into Democrats, including the Bidens. In fact, he never complained about this at the time of his very public termination. If John Bolton said this, it was only to sell a book," Mr Trump, a noted night owl, tweeted just after midnight.

Around sunrise in Washington, the president fired off this tweet: "The Democrat controlled House never even asked John Bolton to testify. It is up to them, not up to the Senate!" Mr Trump appears to be trying to keep Mr Bolton's testimony out of the Senate trial. That's because the Senate's impeachment rules limit the evidence the senator-jurists can consider only to information the House uncovered during its investigation last year.

"There can be no doubt now that Mr Bolton directly contradicts the heart of the President's defence and therefore must be called as a witness at the impeachment trial of President Trump," the seven House Democratic impeachment managers said in a statement that dubbed the book details "explosive".

"Senators should insist that Mr. Bolton be called as a witness, and provide his notes and other relevant documents," the Democratic managers said. "The Senate trial must seek the full truth and Mr Bolton has vital information to provide. There is no defensible reason to wait until his book is published, when the information he has to offer is critical to the most important decision Senators must now make – whether to convict the President of impeachable offences."

Mr Schiff said on Sunday night that the revelations in the coming book show why Mr Trump is threatening to invoke executive privilege to block his former national security point man's testimony.

"Bolton directly contradicts the heart of the President's defence," the California Democrat wrote in a tweet. "If the trial is to be fair, Senators must insist that Mr Bolton be called as a witness, and provide his notes and other documents."

Should four GOP senators join the 47 Democrats in supporting a measure expected on the chamber floor this week to mandate calling Mr Bolton as a witness, it likely would set up a court fight with the White House over the true scope of executive privilege.

The prospect of a lengthy court fight, however, did not stop senior Democrats from immediately demanding Mr Bolton testify.

"John Bolton has the evidence," Senate Minority Leader Chuck Schumer said on Sunday evening.

"It's up to four Senate Republicans to ensure that John Bolton, Mick Mulvaney, and the others with direct knowledge of President Trump's actions testify in the Senate trial," the New York Democrat said in a tweet.

Senator Amy Klobuchar of Minnesota, a Democratic presidential candidate, also said the manuscript means Republicans should join her party in voting to call Mr Bolton as a witness.

"As I've said all week, the truth will come out. And it just did. Testify," Ms Klobuchar tweeted.

Spokespersons for those five GOP senators, as well as Mr Trump, had not responded for requests for comment.

Mr Trump said recently that Mr Bolton would have little to add during the Senate trial, contending he was not involved in the White House's internal Ukraine policy deliberations. Mr Bolton, however, has said he would testify if called, prompting Mr Trump to threaten to invoke privilege – and a likely court battle.

The book no doubt will ignite a debate over the legal bounds of executive privilege – and could mean Mr Trump will deliver his State of the Union address on 4 February before he is expected to be acquitted by the Senate.

One of his hand-pick impeachment attorneys, Alan Dershowitz, has long advocated for the concept of so-called blanket privilege. Under this theory, a president has the authority to block the testimony of some of his closest aides to ensure that individual and those that might follow them in their positions feel they can give the commander in chief candid advice

"Each branch of the government has a form of executive privilege," Mr Dershowitz told Fox News last summer. "The president is perfectly entitled to invoke executive privilege. If they think it goes too far ... let the courts decide."

But for every believer in an expansive executive privilege, there are as many sceptics.

"It should be clear that the privilege does not apply to impeachment," Jonathan Shaub, assistant solicitor general for the state of Tennessee, wrote recently for Lawfare. "The executive's privilege, in my view, is limited to oversight. ... As a result, executive privilege--and all its attendant prophylactic doctrines--should be set aside."