Donald Trump “thinks differently” than any other client, former White House counsel Don McGahn said on Friday.

He also insisted Trump never wavered on the supreme court nomination of Brett Kavanaugh, a statement contradicted by recent reporting.

McGahn spoke at a Florida conference staged by the Federalist Society, a conservative group which has driven Trump’s transformation of the federal judiciary.

When advisers tell the president something is impossible, McGahn said, Trump will pursue it anyway and “then it works”.

“He goes through a decision-tree faster than anyone I’ve seen, to get where he thinks the situation is going to go,” McGahn said. “He thinks differently than anyone else I’ve represented.”

Such remarks should not necessarily be taken as unqualified praise. Many accounts of the Trump White House have focused on how the president ignores detailed briefing materials and makes key decisions on the fly, frustrating such close aides.

The most important man in the world could not get through to his own lawyer. McGahn was deliberately not taking the call Ruth Marcus

According to A Very Stable Genius by the Washington Post reporters Carol Leonnig and Philip Rucker, for example, the pressures of the Oval Office and the Mueller investigation into Russian election interference meant that by summer 2018, when McGahn left the White House, he and Trump “were barely on speaking terms”.

McGahn emerged as a key witness in the investigation carried out by Robert Mueller, the special counsel. In Supreme Ambition, Brett Kavanaugh and the Conservative Takeover, Post columnist Ruth Marcus writes that Mueller “offered a window into the Trump-McGahn dysfunction.

“It described McGahn’s refusal to comply with Trump’s order that he instruct the justice department to fire Mueller … and detailed how Trump called his counsel a ‘lying bastard’ after news reports of the showdown surfaced”.

McGahn unarguably played a key role on Trump’s 2016 campaign and steered the successful nominations of two supreme court justices, Neil Gorsuch and Kavanaugh, and scores of lower court judges. With the cooperation of the Senate majority leader, Mitch McConnell, a roadblock to confirmations under Barack Obama, 187 federal judges have been installed on the bench.

Many observers see this as nothing less than a transformation of the federal judiciary, pushing it strongly right. Many such judges have been suggested by the Federalist Society, which is led by Leonard Leo, a key figure in conservative Washington.

Kavanaugh’s nomination was threatened by accusations of sexual assault from when the judge was a young man, which Kavanaugh strongly denied. In Florida, speaking as Trump seemed assured of survival in his Senate impeachment trial, McGahn said the president never considered withdrawing the Kavanaugh selection.

Marcus, however, writes that during the nomination process, “the president and his counsel remained so at odds that Trump was reluctant to meet with McGahn alone”.

She also reports that after accuser Dr Christine Blasey Ford testified before the Senate judiciary committee, Trump called McGahn “not once, not twice, but several times, trying to reach his counsel.

“The most important man in the world could not get through to his own lawyer. McGahn was deliberately not taking the call. He suspected that Trump, watching Ford’s performance and seeing the reaction, was calling to instruct him to pull the nomination, to say Kavanaugh needed to withdraw.

“On Fox News, Chris Wallace had called Ford’s testimony ‘extremely emotional, extremely raw and extremely credible,’ adding, ‘This is a disaster for the Republicans.’ Trump was nothing if not responsive to such views.”

Marcus also reports that the president asked “outside advisers” whether Kavanaugh should be withdrawn, before McConnell stiffened his spine, telling him the nomination was “only at halftime”.

White House officials later said Trump was not wavering but instead seeking to ask McGahn to tell Kavanaugh to “buck up”.

“McGahn’s deputy contacted him with an urgent message,” Marcus writes. “The president’s trying to reach you, you’ve got to return his phone call. McGahn’s response … was curt, even insubordinate: ‘I don’t talk to quitters.’”

McGahn was pushed out as he prepared to quit. In Florida, he was asked about establishment Republicans who have questioned why he joined Trump’s team. In his answer, he pointed to hard political reality: the judges Trump has appointed.

“The list goes on-and-on,” he said. “That’s my answer to whatever genius said I can’t believe Don is standing next to Donald Trump.”

Another remark seemed sure to provoke liberal ire: McGahn lamented the hyper-partisan nature of judicial nominations, saying some circuit judge confirmation hearings now have the intensity of a supreme court nomination 30 years ago.