Trump surrounded himself with yes-men who treated him like a cult leader. As his impeachment trial looms, that could prove a disaster.

• President Trump is on the back foot thanks to an intervention by Lev Parnas, a once-fanatical supporter involved in the Ukraine shadow diplomacy which prompted Trump's impeachment.
• Ahead of Trump's trial in the Senate, Parnas emerged with a slew of allegations which make the president's position even more difficult to defend.
• In a tell-all interview, Parnas spoke of a cult-like devotion to Trump which inverted after he was discarded.
• The dynamic echoes that of Michael Cohen, another zealous Trump ally who turned on him.
• Relying on, then discarding, hyper-loyal followers has smoothed Trump's path in the short term, but proved damaging further down the line.
• Given the sensitive political dynamic at play going in to his trial, it could prove more costly than Trump imagined.
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As he heads closer to becoming only the third president in US history to face an impeachment trial in the Senate, a familiar pattern is emerging in the associations that got President Donald Trump in this position.

At the same time, expectations that he could speed through the process with a fast, clean acquittal are beginning to evaporate.

A striking interview with a figure from the Ukraine pressure campaign underpinning the case of impeachment helps illustrate how Trump finds himself in this bind.

Lev Parnas, an associate of Trump's lawyer Rudy Giuliani, gave a long interview to MSNBC's Rachel Maddow in which he described at great length the mechanics and experience of enacting shadow foreign policy on behalf of the White House.

Pursued by federal prosecutors on unrelated campaign finance violation charges, Parnas broke his silence for reasons he is yet to fully explain.

According to Maddow, he seems motivated mainly by fear, and perhaps the prospect of lenient treatment.

Speaking out now, he told Maddow he feels like somebody who had just emerged, blinking, from a cult.

He described a sense of unthinking idolatry when doing Trump's bidding and belief that the president would help protect him. He told The New York Times that he "thought by listening to the president and his attorney that I couldn't possibly get in trouble or do anything wrong."

Parnas even had a shrine to Trump in his house.

This cult-like devotion in those who surround Trump is not unique to Parnas. Michael Cohen, Trump's former fixer and attorney, also described a fanatical dedication to the president.

A friend of Cohen's, cited last February by the Times, said of Cohen: "Michael would describe it as being something akin to a cult ... Michael got sucked into it. And his life is in shambles because of it."

It led him to unquestioningly make an illegal payment of hush-money to the porn star Stormy Daniels, for fear of her going public about her relationship with Trump in the fractious 2016 election campaign.

It also led him to helping for years to conceal the payment, under intense pressure, in the hope of a pardon which never came.

James Comey, the former FBI chief, has spoken of what he considered an attempt by Trump in the early days of his presidency to draw him into this dynamic, compromising the traditional firewall between the FBI and the White House.

Comey said the closest comparison he could imagine was with the New York mobsters whom he prosecuted earlier in his career.

It is undeniable that this devotion is useful in the short term - especially when creating loyal group of Republican lawmakers to defend him, fearful of retribution.

Trump is notoriously unimpressed by people who call on other loyalties as they question or frustrate his agenda. And he prizes a close group of loyal footsoldiers, often his children, who streamline the process of getting things done.

Until they don't.

Cohen, like Parnas, turned on Trump in public interviews at a moment of maximum damage.

In a Congressional hearing timed to steal the limelight from Trump's ultimately frustrated efforts to build bridges with North Korea, Cohen called Trump and liar and a racist, whom he claimed asked him, in turn, to lie and threaten on his behalf.

Now the pattern has repeated with the allegations brought forth by Parnas, who sought to confirm that the shady Ukraine agenda apparently pursued by Trump was more extensive than previously known, both in scope and by the sheer number of Trump officials Parnas claims were involved.

The stakes are far from academic. As the Senate trial looms, Republican leadership will try its utmost to enforce total discipline and use its three-seat majority to acquit Trump as swiftly as possible. This would limit the damage of impeachment and open the way - as with the Russia investigation - for the president to claim "total exoneration."

But this unity is shaky. Three Republicans in toss-up seats seem willing to side with Democrats to defy Senate Majority Leader Mitch McConnell and call witnesses to testify in the trial. A fourth would make it a reality.

Witness testimony could mean more revelations from the likes of former national security adviser John Bolton, who is widely believed to have information that could damage Trump.

The president, while complaining bitterly of his impeachment, has also tried to wear it as a badge of honor, fundraising hard on the spectacle of what he still characterizes as a partisan witch-hunt.

Despite his famed resilience to scandal, this strategy becomes less and less tenable if credible and damaging information is brought into the public domain and chips away at his support within the GOP.

Trump's base, which he sorely needs to carry him into a second term come November, is famously loyal. But, as Parnas and Cohen have ably proved, loyalty has its limits.