Vladimir Putin exploited Donald Trump’s “ego and insecurities” to exert an almost mesmeric hold over the former US president, who refused to entertain any negative evaluation of the autocratic Russian leader from his own staff, and ultimately fired his national security adviser, HR McMaster, over it.

The bold assessment of Trump’s fealty to Putin comes in McMaster’s book At War With Ourselves: My Tour of Duty in the Trump White House, published by HarperCollins and arriving on 27 August. The Guardian obtained a copy.

“After over a year in this job, I cannot understand Putin’s hold on Trump,” McMaster recalls saying in the memoir covering the turbulent 457 days the now retired general served as national security adviser from February 2017 until he was effectively fired by tweet in April 2018.

The comment, to McMaster’s wife, Katie, came in the aftermath of the poisoning in the UK by Putin’s agents of Sergei Skripal, a Russian former intelligence officer, and his daughter, in March 2018.

While other western leaders were beginning to formulate a strong response to the assassination attempt, McMaster says, Trump sat in the White House fawning over a New York Post article with the headline: “Putin heaps praise on Trump, pans US politics”. Trump, according to the book, wrote an appreciative note on the article with a black Sharpie and asked McMaster “to get the clipping to Putin”.

“I was certain that Putin would use Trump’s annotated clipping to embarrass him and provide cover for the attack,” McMaster writes.

He said he handed the note to the White House office of the staff secretary, which handles Oval Office communications.

“Later, as evidence mounted that the Kremlin, and very likely Putin himself had ordered the nerve agent attack on Skripal, I told them not to send it.”

In reality, McMaster says, Putin’s apparent simpering over Trump was a calculated effort by the Russian leader to exploit the president and drive a wedge between him and hawkish advisers in Washington DC such as McMaster urging the US to take a harder line with the Kremlin.

“Putin, a ruthless former KGB operator, played to Trump’s ego and insecurities with flattery,” McMaster writes.

“Putin had described Trump as ‘a very outstanding person, talented, without any doubt’, and Trump had revealed his vulnerability to this approach, his affinity for strongmen, and his belief that he alone could forge a good relationship with Putin.

“Like his predecessors George W Bush and Barack Obama, Trump was overconfident in his ability to improve relations with the dictator in the Kremlin. The fact that most foreign policy experts in Washington advocated for a tough approach to the Kremlin seemed only to drive the president to the opposite approach.”

McMaster describes how Trump became obsessed by the Mueller report into Russian meddling in the 2016 presidential election to the point that “discussions of Putin and Russia were difficult to have”.

He says Trump “connected all topics involving Russia” to the report, and allegations by Democrats and other opponents that his campaign, and Trump personally, had colluded with “Russia’s disinformation campaign” to swing the election.

Although special counsel Mueller found no evidence of a criminal conspiracy, he found multiple incidents in which the Trump campaign tried to obscure its contact with Russian operatives, and that Trump himself tried to interfere with or block the inquiry.

When McMaster observed at a security conference in February 2018 in Munich that Mueller had indicted more than a dozen Russian agents for election interference, Trump tweeted a snarky response that the general had “failed” to point out that the election result had not been changed or affected by the Russian efforts.

It was one of a number of broadsides from Trump that signified an increasingly fractured relationship with McMaster, almost all over Russia, that resulted in his ouster barely a month later.

“On Putin and Russia, I had been swimming upstream with the president from the beginning,” writes McMaster, whose successor as national security adviser, John Bolton, also ended up falling out with the president and went on to become one of numerous former administration officials to condemn Trump’s re-election effort.

McMaster recalls another episode in which he was castigated by Trump, at a July 2017 summit in Hamburg, Germany, which became famous for what the Guardian described at the time as a “budding bromance” between the US and Russian leaders as they spent hours locked in private conversation.

“My basic message during the final prep meeting at the Hamburg Messe convention center was ‘do not be a chump’,” McMaster writes, noting that he told the president what Putin sought, including the US to abandon Ukraine, and withdraw US forces from Syria and Afghanistan, which Trump later ordered.

“I told Trump how Putin had duped Bush and Obama. ‘Mr President, he is the best liar in the world.’ I suggested that Putin was confident he could ‘play’ Trump and get what he wanted, sanctions relief and the US out of Syria and Afghanistan on the cheap, by manipulating Trump with ambiguous promises of a ‘better relationship’. He would offer cooperation on counterterrorism, cybersecurity and arms control.

“I could tell that Trump was getting impatient with my ‘negative vibe’. I said what I needed to say. If he was going to be contrary, I hoped he would be contrary to the Russian dictator, not to me.”

Despite the strained relationship with Trump chronicled in his book, and criticisms of the former president therein, McMaster never joined the ranks of other former administration officials eager to castigate him once he left office.

McMaster insists he remained apolitical during his service, looking out only for the interests of the US, and wrote the book to “get past the hyper-partisanship and explain what really happened”.

He recalls how family members joined him in his office on his last day in April 2018, and the then vice-president, Mike Pence, came by to ask them all to step briefly into the Oval Office.

“Trump was gracious,” McMaster writes.

“[He] pointed his finger at my four nieces and nephews: ‘Your uncle is a great guy, very tough, and he did a fantastic job for me. Make sure he only writes nice things about me.’”