LONDON — In the melee that was the British Parliament last week, at least one person seemed to revel in the brutal politics of the Prime Minister Boris Johnson era.
In his customary crumpled white shirt, Dominic Cummings, the prime minister’s chief aide, could be heard cursing over the phone at lawmakers and seen prowling the corridors of Parliament, laying waste to the careers of Conservative politicians who stood in the way of an abrupt withdrawal from the European Union.
He saved some opprobrium for the opposition, too, interrupting a tipsy, late-night stroll to goad the opposition Labour leader, Jeremy Corbyn, into backing an early election, a Labour lawmaker recounted publicly. “Don’t be scared!” Mr. Cummings screamed.
Throughout the first weeks of Mr. Johnson’s leadership, Mr. Cummings was a shadowy figure, depicted as the Rasputin directing his boss’s scorched-earth strategy to deliver Brexit by Oct. 31, with or without a deal governing future relations, “come what may.”
To his fans he was a genius, the man who directed the successful Leave campaign in the 2016 referendum and was sure to chain saw his way through the political underbrush to achieve Brexit. To his opponents, he was a genius, but an evil, unprincipled one who would go to any lengths, even subverting the democratic process, to accomplish his goals.
Yet, since Mr. Johnson began unspooling his Brexit strategy, and particularly in this first real week tangling with the reality of Brexit’s complex politics, the mantle of genius has begun to slip from Mr. Cummings’s shoulders.
In a matter of days, Mr. Johnson has been accused of subverting the country’s uncodified constitution by suspending sittings of Parliament, and of fracturing the Tories by banishing 21 lawmakers — including Winston Churchill’s grandson — who voted to try to stop him leaving the European Union without a deal on Oct. 31, if necessary.
That decision drove one of Mr. Johnson’s biggest remaining moderate allies, Amber Rudd, out of his cabinet and the Conservative Party this weekend, with Ms. Rudd saying that leaving the European Union with a deal was no longer “the government’s main objective.”
The prime minister lost his working majority in Parliament and, more worrying for Mr. Cummings, his fallback plan of holding a mid-October general election to secure a mandate for Brexit is looking like a non-starter after opposition parties came together on Friday to say they could not support it.
That would spell defeat for the government on Monday, when it will hold a second parliamentary vote on elections, adding to the prime minister’s troubles just as a bill averting a no-deal Brexit is set to become law.
The resulting chaos has left Britain’s government enfeebled, and its path to leaving the European Union more inscrutable than ever. Lawmakers are now demanding Mr. Cummings’s resignation. Protesters are waving placards with his visage, but embellished with small red horns. Rumors of his imminent firing are gaining traction in Westminster.
Mr. Cummings is said to be plotting a radical response, with Mr. Johnson preparing to defy the law averting a no-deal Brexit by refusing to ask Brussels for a delay, ministers said on Sunday. That could draw the courts into the dispute as the clock ticks down to Oct. 31., a spectacle that Mr. Cummings reckons will only burnish the prime minister’s credibility with pro-Brexit voters far from London.
But it could also drive more moderate voters from the Conservatives for decades. And British news reports said that even Mr. Johnson was concerned that the hardball tactics have backfired.
A serial provocateur, talented strategist and political assassin, Mr. Cummings has built his career on the outrage of the so-called blob, as he calls parts of the establishment. He has no known political affiliation, concentrating his energies on shaking up Britain’s political system.
“Dom has so far been very effective in running campaigns against things,” said David Laws, a former lawmaker from the Liberal Democrats who worked with Mr. Cummings in the Education Department. “Now we’ll see whether he can make the transition into government and create things, rather than smash them up.”
If it seems to the British political class like he has overreached, it is not clear whether Mr. Cummings himself has reached the same conclusion. Some ex-colleagues believe he will be losing little sleep about his pariah status.
“We are in absolute chaos and Dominic loves chaos,” said Matt Sanders, who shared an office with Mr. Cummings for three years in the Education Department. “He has exploded this virtual hand grenade in Westminster and everyone is talking about him. If moderate members of Parliament and voters are screaming about him he will be thinking: ‘I must be doing something right.’”
Mr. Cummings demonstrated many of the same qualities on display lately in the ruthless, no-holds-barred and factually suspect 2016 referendum campaign. (He was later found in contempt of Parliament for refusing to answer lawmakers’ questions about the campaign.)
Resisting right-wing activists who wanted to focus solely on immigration, he appealed to middle-class voters with a message of sovereignty and independence, coining the slogan “Vote leave, take back control.”
His mystique looms so large in the British imagination that, in a recent television drama about Brexit, “The Uncivil War,” he was played by Benedict Cumberbatch, who portrayed a tortured genius intent on detonating Britain’s stodgy political elite.
The son of an oil rig project manager and a special-needs teacher, Mr. Cummings attended Oxford, like so many protagonists of the Brexit saga. But unlike the patrician circle that has tended to surround prime ministers, Mr. Cummings did not immediately leap into the crucible of Westminster politics.
Instead he went to Russia, where he tried and failed to launch an airline in a venture so mismanaged that, so the story goes, the one customer it managed to attract was left behind by the aircraft. In Britain, he also helped out as a nightclub doorman.
Mr. Cummings entered politics without any of the party loyalty or the ambition about becoming a lawmaker that drives most young aides. But he soon made a name for himself and, as the chief of staff to a Conservative minister, Michael Gove, at the Education Department starting in 2010, embarked on a reign of fear.
“Politics is a brutal business, but even in that world, Dom’s approach is highly unusual,” Mr. Laws said. “It sort of makes everyday politics look like a very cozy, consensual affair, because this is brutalism plus-plus-plus.”
He viciously undermined the Liberal Democrats who were then in a coalition with the Conservatives, but did not spare his own. “The Conservative Party for him was a useful tool in destroying things and then rebuilding them,” Mr. Sanders said.
That disdain for the political establishment served him well during the 2016 campaign, when Mr. Cummings clashed with Tory veterans of the anti-Europe crusade. Mr. Cummings fashioned himself a futurist, intent on unshackling Britain from the European Union so it could attract talent and build a more efficient, technically advanced society.
His approach attracted the attention of Mr. Johnson, one of the highest-profile Brexit backers.
“They both have sort of magpie eyes for any shiny new idea which might or might not work, and they’re prepared to go well beyond the bounds of the usual conventions,” said Andrew Gimson, who wrote a biography of the prime minister.
But analysts now wonder whether his disdain for lawmakers, coupled with Mr. Johnson’s own unfamiliarity with parliamentary negotiations, may now be a liability.
“He doesn’t know them as individuals,” Mr. Gimson said of Mr. Cummings. “He probably thinks most of them are rather third-rate.”
Many are furious with him, particularly those who have been thrown out of the Conservative Party, such as Dominic Grieve, one of the 21 now former Tory members of Parliament expelled by Mr. Johnson.
“Mr. Cummings is a bashi-bazouk,” said Mr. Grieve, citing the Ottoman Empire’s shock troops, who were renowned for their ferocity. “It is going to be a very difficult period because Cummings doesn’t respect any rule at all.”
Downing Street declined to comment for this article.
Mr. Cummings is not one to easily admit error, and does not waste time worrying about his image. But analysts say he has made himself vulnerable by committing one of the cardinal sins for advisers in the Westminster firmament: raising their profile so high that they risk putting themselves in the firing line.
Then again, he never planned to stay long in the job.
“In his view he is there to deliver Brexit by 31 October or an election victory, he is not there for the long haul,” said Lucy Thomas, a leading figure in the anti-Brexit campaign in 2016. “That makes it easier to stick doggedly to that objective and do anything to get there.”
The next few weeks will tell whether he will succeed, but it is certain to be a bumpy ride.
“Dominic Cummings has an insatiable appetite for risk,” said Mr. Sanders. “He is totally happy taking a gamble.”