British Prime Minister Theresa May has announced that she will resign next month, ending nearly three years in office that will be defined by her inability to pull Britain out of the European Union.

In an emotional statement on Friday Ms. May said she will step down on June 7, clearing the way for the Conservative Party to select a new leader who will become Prime Minister. Ms. May expressed “deep regret” at her failure on Brexit, saying she had done all she could to win approval for a withdrawal agreement with the EU.

“I have done everything I can to convince MPs to back that deal … sadly I have not been able to do so,” she said. “I believe it was right to persevere even when the odds against success seemed high. But it is now clear to me that it is in the best interests of the country for a new Prime Minister to lead that effort.” As she teared up she added: “I will shortly leave the job that has been the honour of my life to hold. The second female Prime Minister, but certainly not the last. I do so with no ill will but with enormous and enduring gratitude to have had the opportunity to serve the country I love.”

The contest to replace her has already begun and a new leader is expected to be in place by the end of July. The front runner is former Foreign Secretary Boris Johnson who has been bitterly critical of Ms. May’s approach to Brexit.

Mr. Johnson paid tribute to Ms. May on Friday, saying on Twitter; “Thank you for your stoical service to our country and the Conservative Party. It is now time to follow her urgings: to come together and deliver Brexit.”

Ms. May’s resignation does little to resolve the Brexit turmoil. The United Kingdom is supposed to leave the EU on Oct. 31, but that deadline has been extended several times already. Ms. May was about to try for a fourth time to win parliamentary approval for a Brexit agreement she struck with the EU last November. But her “new Brexit deal”, unveiled on Tuesday, was met with widespread criticism and several cabinet ministers pressed her to quit. The plan has now been pulled and it’s unclear if Members of Parliament will vote on it when they return from a spring break on June 3.

Mr. Johnson has taken a harder line on Brexit than Ms. May. He has criticized her repeatedly for what he viewed as selling out and negotiating a deal with the EU that keeps Britain far too tied to the bloc. He has vowed to be tougher with the EU and win changes to the deal. He’s also indicated that he’s prepared to leave without any agreement.

It’s not clear if that strategy will have much success. The EU has refused to renegotiate the withdrawal agreement and a majority of British MPs don’t want the country to leave without a deal.

Mr. Johnson “is charismatic where’s she’s not and he’s populist where she’s at least an ineffective populist,” said Tim Bale a professor of politics at Queen Mary University of London. “But he can’t change the mathematics in parliament. He can’t wave a magic wand and get a majority for the kind of Brexit he wants.”

Ms. May came into office with great fanfare in July 2016. She replaced David Cameron as Prime Minister just weeks after the country voted to leave the EU in a referendum. Mr. Cameron campaigned for Britain to remain in the EU and Ms. May was seen by Tory MPs as a pragmatic replacement who could deliver on the referendum result even though she also supported the remain side. She was such a popular choice that she won the leadership by acclamation after every rival dropped out.

Ms. May initially took a tough stance on leaving the EU, saying repeatedly that “Brexit means Brexit and we’re going to make a success of it.” She said the country would pull out of the EU’s single market and customs union, which allow for the free movement of goods and services, and she rejected a Norway-style option that would have kept the U.K. within some EU institutions. “There will be no attempts to remain inside the EU,” she said firmly.

In March 2017 she triggered the EU exit mechanism, known as Article 50 of the Lisbon Treaty, which kicked off a two-year negotiation that she promised would not be extended. Within months she called a snap election in June 2017, saying she needed a larger Conservative majority to give her a stronger mandate to negotiate with the EU.

The campaign went disastrously wrong. Ms. May looked stiff on the campaign trail and failed to connect with voters who were far more concerned about other issues than Brexit. The result was a humiliation for her and the Tories. The party lost its majority in parliament and Ms. May had to form a working coalition with Northern Ireland’s Democratic Unionist Party, or DUP.

From then on Ms. May’s Brexit strategy became muddled and fiercely opposed by a group of Tory MPs who believed she was drifting too far from Brexit. The DUP also challenged her on her plan to avoid a hard border with Ireland by keeping Northern Ireland closely tied to the EU. Cabinet ministers resigned in droves and Ms. May went through three Brexit secretaries, all of whom quit over her strategy.

Her latest Brexit deal included the possibility of the U.K. remaining in the customs union and giving MPs a say on whether to hold a second referendum on Brexit, steps too far for Tory MPs and cabinet ministers who began an open revolt. She also began discussing Brexit options with the opposition Labour Party, infuriating still more Tories. “I do think it went wrong almost immediately because she made the decision to go for a much harder Brexit than would have been necessary to pull the country and indeed parliament together behind her,” said Dr. Bale. “From that moment on she was doomed. Particularly when she lost her majority and didn’t recognize reality and pivot towards a more a kind of cross party consensus style of Brexit. She was utterly lost at that point.”

The Globe and Mail, May 24, 2019