Modeling by YouGov suggests that if an election were to be held now, the Tories would suffer heavy losses in key seats, with Johnson probably also losing his own.

Yet calling an early election — the next one is expected in 2024 but could be held as late as January 2025 — also makes some sense for Johnson. History shows that even prime ministers who win a confidence vote find their authority is undermined; Theresa May won in December 2018 yet was still out of Downing Street months later at the height of Tory wrangling over Brexit.

The calculation may be that Johnson, whose Tories won a commanding parliamentary majority in 2019, can afford to see more than 30 MPs lose their seats and still secure a majority. On that basis even the threat of a snap poll could be effective at dissuading would-be rebels, given some of the MPs urging Johnson to quit are among those at risk.

Read More: Boris Johnson Is Back to Counting Tory Rebels: Five Key Dangers

Talk of a confidence vote in Johnson has grown in recent days, following a steady drip-drip of lawmakers saying he should quit. A civil servant probe into the so-called partygate scandal has damaged Johnson, while many are fed up with his chaotic leadership style and a series of unforced errors and u-turns.

On Tuesday, Conservative MP John Stevenson became the latest to publicly call for Johnson to go, indicating he had written a letter calling for a confidence vote to Graham Brady, who leads the influential 1922 Committee of rank-and-file Tories. Former cabinet minister Andrea Leadsom, who supported Johnson’s campaign to become Tory leader in 2019, also criticized him, though her letter to constituents didn’t say if she has also written to Brady.

So far 28 Conservative MPs have openly said Johnson should resign, with a further 13 being publicly critical. Only Brady knows the true number of MPs calling for a vote.

The expectation that Johnson would win a confidence vote stems from the fact that even though he’s been undermined by partygate, last week’s report did not trigger a mass rebellion. The absence of a major challenge from within his top team of ministers, as well as the size of the so-called payroll vote — Conservative MPs holding government jobs — are also key factors.

Almost half of Tories are in that camp and, in theory, are deemed unlikely to vote for a change of leader if it might risk their current title or post. That can, however, change once a vote is actually called.

Tory MPs were exchanging rumors on Tuesday that Johnson was calling around to shore up support, including offering promises of promotion to potential rebels. Johnson’s press secretary said he had been engaged in phone calls Tuesday, but declined to comment on specifics.

“This prime minister has been reduced to desperately phoning around his mutinous MPs offering out baubles in a doomed attempt to save his own skin,” the opposition Labour Party’s deputy leader Angela Rayner said in a statement. “His disheveled government is asleep at the wheel.”

Several obvious dangers loom for Johnson that could persuade more rebels to show their hand. Conservative MPs are looking at June 23 as potentially a key moment, when the party faces two parliamentary elections that will be a significant test of Johnson’s popularity.

If the Tories were to lose the seats of Wakefield in West Yorkshire and Tiverton and Honiton in southwest England — both up for grabs due to sex scandals involving the sitting Tory MP — that may trigger the confidence vote, one of the MPs speaking to Bloomberg said.

Johnson also faces a parliamentary inquiry into whether he deliberately misled lawmakers over partygate. On Tuesday, his standards adviser Christopher Geidt said there is a “legitimate question” over whether the premier broke the ministerial code after being fined by police.

Geidt, who sits as an independent in the upper House of Lords, called on Johnson to set out his case to the public. In reply, Johnson wrote that he is “fully accountable to Parliament and the British people.”