Their circling of the wagons, she concluded, was “tribal.” As frustrated as they are with Mrs. May, Conservatives are desperate to avoid a change of government that would put Jeremy Corbyn, the head of the Labour Party, in office.

Many of them feel sympathy for her, as well, believing that she was given an impossible task.

“It feels like a parallel universe, doesn’t it, considering where we were last night, just 24 hours ago,” she said. “I have to say, looking at the scenes in the last half-hour or so, it’s the most united the Conservative benches have been, probably, for months.”

A notable tribute to Mrs. May came from Conservative lawmaker Mark Francois, a leader of the arch-Brexiteer European Research Group.

Mr. Francois, in November, submitted a scathing letter to the party’s 1922 committee, which has the power to remove the party leader, saying Mrs. May “just doesn’t listen” and is “in complete denial.” Since then, he has missed no opportunity to criticize her deal, which he described as “rancid,” and complained that, instead of submitting the deal to a vote, members of her government had “gone and run away and hidden in the toilet.”