President Trump poses a “danger for the republic” and would be an even greater threat if he wins a second term this autumn because he would be unconstrained by future electoral considerations, John R. Bolton, his former national security adviser, said in an interview aired on Sunday night.

In one of the most scathing public assessments of a sitting President by such a high-ranking former aide in modern times, Bolton depicted Trump as an “erratic and impulsive” leader who cares only about his own needs, does not fully understand democracy or the Constitution, is played “like a fiddle” by Russia and is not “fit for office”.

“The concern I have, speaking as a conservative Republican, is that once the election is over, if the President wins, the political constraint is gone,” Bolton told Martha Raddatz of ABC News in his first television interview publicising his memoir of 17 months as Trump’s top security adviser. “And because he has no philosophical grounding, there’s no telling what will happen in a second term.”

Bolton’s book, The Room Where It Happened, has become the talk of Washington even before its scheduled publication on Tuesday. The Trump administration went to court to try to block its publication, only to be rejected by a federal judge, and the President has been railing about what he considers Bolton’s betrayal.

But the beginning of the book tour means that Trump will be confronted with the portrait laid out in the volume for days or weeks to come.

Bolton, a veteran of three previous Republican administrations, says in the book that the House should have investigated Trump for impeachment not just for his Ukraine scheme but for his willingness to intervene in criminal investigations on behalf of dictators and otherwise seeking foreign help for his re-election campaign.

In the interview with ABC, he went even further by accusing Trump of lying when the President denied linking American security aid to his demand that Ukraine incriminate his Democratic political rivals, and Bolton dismissed the White House defence at the Senate impeachment trial as “utter nonsense”.

Rather than being deterred by the impeachment trial, he added, Trump became emboldened by his acquittal by the Senate almost entirely along party lines. “He didn’t learn lessons from it, other than that he could get away with it, which leaves only the last guardrail — is the election this November,” Bolton said.

But even as Bolton said Trump had adopted “obstruction of justice as a way of life”, as he put it in the book, House Democrats on Sunday eschewed interest in opening new impeachment proceedings against him.

The chairman of the House Judiciary Committee said it would be a waste of time because Senate Republicans were too “corrupt” to consider Bolton’s statements.

“The Senate Republicans were not interested in any evidence,” the chairman, Representative Jerrold Nadler of New York, said on the CNN programme State of the Union. “They were corrupt in that respect.”

The book’s revelations have been met with frustration from Capitol Hill Democrats, who were angry that the former national security adviser waited until the release of his book — for which he was reportedly paid $2 million — to accuse Trump of misdeeds that went far beyond those for which he was impeached. At the same time, Republicans dismissed the book as either false or motivated by money.

Peter Navarro, Trump’s trade adviser, appeared on the programme and disputed several claims in Bolton’s book. He also said Bolton should be prosecuted.

New York Times News Service