• She will resign as party leader on June 7, but stay on as prime minister until a successor is chosen.

• Her departure comes after she repeatedly failed to win Parliament’s approval for a deal to withdraw Britain from the European Union.

• “I have done everything I can,” Mrs. May said. But she added that it was in the “best interests of the country for a new prime minister” to lead Britain through the Brexit process.

• The breaking point comes at an awkward moment, with President Trump scheduled to arrive in Britain on June 3 for a state visit.

The announcement “could set off a ferocious succession contest within her governing Conservative Party,” Mr. Castle writes. The former foreign secretary, Boris Johnson; the former Brexit secretary, Dominic Raab; and Andrea Leadsom, who had quit as leader of the House of Commons on Wednesday, are all seen as likely contenders.

It leaves Britain’s future more uncertain than ever, with no clearly favorable route out of the E.U., nor any obvious plan to stay in the bloc either. Mrs. May’s successor has a tough task ahead.

Trump hints at leniency toward Huawei

President Trump issued contradictory messages about the Chinese technology giant yesterday, calling Huawei a “very dangerous” security threat — but also hinting that it could be part of a trade deal with China. Here’s what he said:

“Huawei is something that’s very dangerous. You look at what they’ve done from a security standpoint, from a military standpoint, it’s very dangerous. So it’s possible that Huawei even would be included in some kind of a trade deal. If we made a deal, I could imagine Huawei being possibly included in some form, some part of a trade deal.”

He offered no specifics of what that might look like. When pushed for details, Mr. Trump responded: “Oh it’s too early to say. We’re just very concerned about Huawei from a security standpoint.”