Trump and Johnson Were Accused of Breaking Rules. One Lost Party Support.

An angry, aggrieved former leader attacks the institutions he once led for accusing him of flouting the rules and lying about it. His allies whip up supporters against what they call a witch hunt. A country watches nervously, worried that this flamboyant, norm-busting figure could cause lasting damage.

There are obvious parallels in the political tempests convulsing Britain and the United States, but also stark differences: Former President Donald J. Trump faces federal criminal charges while Boris Johnson was judged to be deceitful about attending parties. And yet, Britain’s Conservative Party has regularly stood up to Mr. Johnson while the Republican Party is still mostly in thrall to Mr. Trump.

Conservative lawmakers in Britain form the majority on a committee that found Mr. Johnson, a former prime minister, had deliberately misled Parliament over lockdown-breaking parties in Downing Street during the coronavirus pandemic. Mr. Johnson’s conduct, they said, would have warranted a 90-day suspension from the House of Commons had he not preemptively resigned his seat in protest last week.

On Monday, the House of Commons will vote on whether to accept or reject the committee’s findings. The government said it would not pressure Tory lawmakers to vote one way or the other. That sets up a potential repudiation of Mr. Johnson by his party that could go far beyond the token number of Republican lawmakers in the House of Representatives who voted to impeach Mr. Trump in 2019 and 2021.

Even before the vote on Monday, the condemnation of Mr. Johnson by his Tory colleagues on the privileges committee was striking. Not only was it a stinging rebuke of a popular, if factually challenged, politician, but it was also a clarion call for the restoration of truth as the bedrock principle in a democracy.

“The outcome is much worse than expected,” said Kim Darroch, a former British ambassador to Washington, who noted that the committee had been expected to recommend at most a 30-day suspension. “Its severity suggests the committee had a broader purpose in their decision: that of reaffirming the fundamental importance of truth in British politics.”

“There is a read across to the situation in the U.S.,” said Mr. Darroch, noting the fierce debates over truth in the American political discourse.

While a few Republicans, like former Gov. Chris Christie of New Jersey and Senator Mitt Romney of Utah, have called out Mr. Trump for his erroneous statements, many more have stayed quiet — implicitly or explicitly accepting his false claim that he won the 2020 presidential election, for example.

So far, the multiple indictments of Mr. Trump have yet to shake most Republicans from their support for him. His arraignment this week on charges of mishandling classified documents and obstructing justice brought fresh cries from Republican leaders like Speaker Kevin McCarthy of the House that President Biden was “weaponizing” the Justice Department to go after his political enemies.

Mr. Johnson has deployed similar charges against the committee. In a vitriolic statement after its report was made public, he said, “This decision means that no M.P. is free from vendetta, or expulsion on trumped-up charges by a tiny minority who want to see him or her gone from the Commons.”

The language was vintage Trump, if clothed in an English accent. The committee’s report, Mr. Johnson declared, was “rubbish,” “deranged” and a “complete load of tripe.”

He accused a senior Tory committee member, Bernard Jenkin, of breaching lockdown rules by attending a gathering to celebrate a birthday. And he veered into obscure personal jibes, describing one of the report’s claims as “an argument so threadbare it belongs in one of Bernard Jenkin’s nudist colonies.”

“This is all straight out of the Trump playbook,” said Frank Luntz, an American political strategist, noting that Mr. Trump had influenced the language of other world leaders. “He’s condemning the messenger, similar to Trump in the U.S., Netanyahu in Israel and Bolsonaro in Brazil.”

Mr. Luntz, who knew Mr. Johnson when they were students at Oxford University, said he was surprised that Mr. Johnson had resorted to that language. Mr. Luntz has long resisted comparisons of Mr. Johnson and Mr. Trump, saying that “Boris has written more books than Trump has read.”

But having spent two days this week in Parliament, Mr. Luntz said his overriding sense was that Mr. Johnson had little support and that most Conservatives simply wanted to put the drama behind them.

Very few Conservatives have taken up Mr. Johnson’s cry of a political vendetta. Many pointed out that not a single lawmaker sought to block his referral to the privileges committee in April 2022, when the questions about the veracity of his statements to Parliament about the parties had reached a crescendo.

The committee reflects the party balance in the House, with four members from the Conservatives, two from the opposition Labour Party and one from the Scottish National Party. By tradition, it is chaired by a lawmaker from the main opposition party, in this case Harriet Harman, whom Mr. Johnson accused of having the “sole political objective of finding me guilty and expelling me from Parliament.”

Unlike Mr. Trump, whose personal attacks often go unanswered, the committee lashed back at Mr. Johnson. It accused him of “impugning the committee and, thereby, undermining the democratic process of the House” and “being complicit in the campaign of abuse and attempted intimidation of the committee.” It plans a special report into Mr. Johnson’s behavior during the inquiry.

While Mr. Johnson delivered a landslide majority for the Conservatives less than four years ago — and he remains popular in some Tory precincts — he has never had the kind of iron grip over the party that Mr. Trump has.

In September 2019, Conservative rebels staged an insurrection, blocking his plan to withdraw from the European Union without an agreement with Brussels. Last summer, Mr. Johnson was forced to resign as prime minister after the wholesale resignation of members of his government, amid the allegations about Downing Street parties and sex offenses of a senior Conservative official.

But not until this week has Mr. Johnson faced a reckoning for what his critics say is a career — first as a journalist and later as politician — built on bending the facts and gleefully disregarding the rules. For those who have known Mr. Johnson for a long time, the sense of satisfaction was palpable.

“It’s the first time where he has finally been caught out,” said Sonia Purnell, who worked with Mr. Johnson in the Brussels bureau of The Daily Telegraph in the 1990s and wrote a critical biography of him. “If he hadn’t been caught out today, that would have been pretty much a mortal blow to British democracy.”