While many critics of Britain’s withdrawal from the European Union hope that an early general election will give them a chance to obstruct the process, current opinion polls suggest it will do the opposite, strengthening Mrs. May’s power to force through any deal she negotiates.
If her Conservative Party wins a majority, Mrs. May would not be required to call another general election until 2022. That would allow for much more time to build a new relationship with the European Union and would lessen the chances of a disorderly departure from the bloc — often likened to walking off a cliff edge.
Analysts warned, however, that this did not necessarily mean that Mrs. May would seek a close relationship with the European Union after Britain has completed its departure.
“It gives more freedom of maneuver, it means that she can ignore everyone because she has a loyal party behind her,” said Anand Menon, a professor of European politics and foreign affairs at King’s College London, speaking of the prime minister’s position if the Conservative Party were to significantly increase its number of seats in the House of Commons.
“That gives her added momentum, though I don’t necessarily think that the momentum is towards the soft side of Brexit,” he added, referring to a type of withdrawal that would maintain closer economic relations with the European Union.
Last month, Mrs. May formally triggered the two-year procedure for leaving the European Union, setting a March 2019 deadline for departure. The talks are expected to be difficult, and those complications were highlighted by Mrs. May as a reason for reversing numerous pledges that she would wait until 2020 to hold the next national vote.
If Britain were to stick with the next scheduled general election date, in May 2020, “the negotiations would reach their most difficult and sensitive stage just as an election was looming on the horizon,” Mrs. May said. She said her Conservative Party needed a new mandate: “Five years of strong and stable leadership, to see us through the negotiations.”
Even though opinion polls show that the Conservative Party is likely to perform strongly, lawmakers from the opposition parties went along with Mrs. May’s call, perhaps out of fear that resisting an early election would make them look weak.
“We welcome the opportunity for an early election,” the leader of the opposition Labour Party, Jeremy Corbyn, said, before describing Mrs. May as “a prime minister who cannot be trusted” for her about-turn on the election.
“This election is about her government’s failure to rebuild the economy and living standards for the majority,” Mr. Corbyn said, as he tried to shift the focus away from Britain’s exit from the European Union, an issue on which his party is badly divided.
Mr. Corbyn condemned Mrs. May’s reluctance to participate in a televised debate with other party leaders before the election, as has Tim Farron, the leader of another opposition party, the centrist, pro-Europe Liberal Democrats.
But Mrs. May said Mr. Corbyn would “bankrupt our economy, weaken out defenses and is simply not fit to lead.”
In a separate development, Nick Clegg, a former deputy prime minister who led the Liberal Democrats to a crushing defeat in 2015, said he would seek to remain in Parliament, quashing speculation that he might withdraw from politics.
But George Osborne, the Conservative former chancellor of the Exchequer, will not run again, said The Evening Standard, the London newspaper that has hired Mr. Osborne as its new editor.
A general election adds to a period of extraordinary turbulence in British politics. Mrs. May’s predecessor, David Cameron, won his unexpected, if small, majority in Parliamentary in 2015, and soon afterward Labour took a hard left turn, electing Mr. Corbyn as its leader. Then Mr. Cameron, who favored remaining in the European Union, lost his referendum bet last year, resulting in a reversal of four decades of European integration and creating extreme uncertainty over Britain’s future economic ties to its closest partners.
Voters are unlikely to relish the prospect of another election and, given the volatility of politics, it is possible — though unlikely — that Mrs. May’s decision could backfire. Among other things, critics argue that she risks sacrificing her image as a straight player.
In an interview with the BBC on Wednesday, Mrs. May said her opponents in Parliament had sought to “frustrate the Brexit process,” but she conceded that she had suffered no defeats in the House of Commons on the issue.
Many analysts say that the prime minister simply was unable to resist taking advantage of very strong support in opinion polls for the Conservative Party.
After Mrs. May’s announcement on Tuesday, the pound rose against other currencies, suggesting that the financial markets believe that Mrs. May will win a larger majority in Parliament and a smoother path to leaving the European Union.
Professor Menon noted, however, that new Conservative lawmakers might be even more opposed to the bloc than current ones. And with a strengthened position in Parliament, Mrs. May would be able to blame European Union negotiators if she did not get the deal she wanted.