LONDON — The end, when it finally came, was just as chaotic, messy and jaw-dropping as every other chapter of Boris Johnson’s political career.
Holed up in Downing Street on Wednesday night, the prime minister faced an open rebellion of his cabinet, a catastrophic loss of support in his Conservative Party and a wholesale exodus of ministers, which threatened to leave significant parts of the British government without functioning leadership.
Yet far from surrendering, Mr. Johnson’s aides put out word that he would continue to fight. It looked like a last roll of the dice by one of the great gamblers in British politics. His brazen refusal to bow to reality invited comparisons to Donald J. Trump’s defiance in the chaotic days after he lost the 2020 presidential election.
By Thursday morning, however, political gravity had finally reasserted itself. For one of the few times in his career, Mr. Johnson was unable to bend the narrative to his advantage through the sheer force of his personality.
At midday, the prime minister went to a lectern in front of 10 Downing Street to announce he was relinquishing the leadership of a party that no longer supported him, and giving up a job he had pursued for much of his adult life.
“I want to tell you how sorry I am to be giving up the best job in the world,” Mr. Johnson said. Then, defusing the solemnity of the moment with a wry line from the pool halls of America, he added, “Them’s the breaks.”
As the political post-mortems on Mr. Johnson are written, the tumultuous events of the last week may come to encapsulate his career — one defined by a gleeful disregard for the rules, a shrewd instinct for public opinion, an elastic approach to ethics and a Falstaffian appetite for the cut-and-thrust of politics.
“Most prime ministers would have gotten the message sooner,” said Andrew Gimson, one of Mr. Johnson’s biographers. “The element of exaggeration, of turning up the volume, is very characteristic of his style.”
Mr. Gimson once likened Mr. Johnson to Admiral Nelson, the 18th-century naval hero who vanquished Napoleon in the Battle of Trafalgar. “Nelson said the boldest measures are the safest,” he said.
In the end, however, Mr. Johnson’s risk-taking bravado was not enough to compensate for his shortcomings. He engaged in behavior that critics said revealed a sense of entitlement and a belief that the rules did not apply to him, his staff or his loyalists. Critics accused him of being disorganized, ideologically and administratively.
After leading Britain out of the European Union in 2020, the prime minister did not have much of a plan for what to do next. He quickly became hostage to events, lurching from crisis to crisis as the coronavirus pandemic engulfed Britain. A pattern of scandals, which followed him throughout his career, soon overtook Downing Street.
Mr. Johnson had long thrived by thumbing his nose at political convention. His disheveled crop of blonde hair seemed a metaphor for a messy personal and professional life, which some British voters savored while others merely tolerated it.
But Mr. Johnson’s lack of truthfulness finally caught up with him. His constantly shifting accounts of his conduct — whether in attending illicit parties at Downing Street during lockdowns, attempting to use a Tory Party donor to finance the costly refurbishment of his apartment, or promoting a Conservative lawmaker with a history of sexual misconduct allegations against him — finally exhausted the patience of his party and many voters.
Mr. Johnson’s role in campaigning to leave the European Union, then carrying out Brexit and then seeing Britain through the pandemic, will guarantee him a place in the ranks of significant British prime ministers. Beyond that, he leaves behind a checkered policy legacy, and he never escaped suspicions that his agenda was driven not by ideological conviction but by the cynical calculation of what political advantages he could extract from it.
In the end he may be most remembered for his confounding mix of strengths and weaknesses.
From the start, Mr. Johnson represented something new in British politics. A journalist-turned-politician, he was able to fuse the forces of celebrity culture with an opportunistic, ideologically flexible approach to the issues. To most Britons, he was simply “Boris,” a first-name familiarity enjoyed by no other British politician.
July 7, 2022, 12:34 p.m. ET
With his rumpled suits and untucked shirts, Mr. Johnson affected a louche, upper-class insouciance that somehow also connected with working-class voters. His antics as the mayor of London — he once famously dangled from a zip line above photographers, waving a pair of Union Jacks — turned him into a clown prince.
But all the tomfoolery — aside from drawing attention to himself — also helped make him a serious electoral contender. With Britain caught up in an anguished debate over its future in the European Union, Mr. Johnson latched on to an issue that would propel him to the top of the Conservative Party. First, of course, he famously dithered about which side of the Brexit debate to embrace — leave or remain — drafting newspaper columns that made the case for both.
Once he had thrown in his lot with “Vote Leave,” Mr. Johnson became an energetic campaigner. He helped win the 2016 referendum against European Union membership, used the issue to drive out the woman who became prime minister in its aftermath, Theresa May, and rode a promise to “Get Brexit Done” to a thrashing of the Labour Party in the 2019 general election.
That victory, which awarded the Conservative Party its largest majority since 1987, emboldened Mr. Johnson when his standing collapsed under the weight of serial ethical scandals. He invoked his “colossal mandate” as a response to those who said he should step down, saying he owed it to his 14 million voters to go on.
Unlike in the United States, however, Mr. Johnson governs in a parliamentary, not a presidential, system. Those 14 million people voted for the Conservative Party, not for Mr. Johnson, who merely served as the party’s leader, at the pleasure of its lawmakers. When they withdraw that support, the leader is replaced.
At a parliamentary committee hearing on Wednesday, Mr. Johnson pointedly declined to rule out trying to call an early general election — in effect, bypassing the Conservative Party to throw his fate back to the voters.
That evening, a delegation of cabinet ministers and party officials traveled to Downing Street to appeal to Mr. Johnson to step down. He rejected their entreaties and instead fired one of his most senior ministers and allies, Michael Gove, who had been among those warning him that his time was up.
The palace intrigue, combined with Mr. Johnson’s initial refusal to accept his situation, drew comparisons to Mr. Trump.
“We have this habit in Britain of following American politics, a couple of years later,” said Jonathan Powell, who served as chief of staff to a Labour prime minister, Tony Blair. “We have ended up with a poor man’s Trump, in the form of Johnson.”
The United States, Mr. Powell said, was still living with the aftereffects of Mr. Trump’s presidency. “In Britain, because our system is different, we should be in a position to heal more quickly,” he said.
