One Trump confidant likened the president to a whistling teapot, saying that when he does not blow off steam, he can turn into a pressure cooker and explode. “I think we are in pressure cooker territory,” said this person, who spoke on the condition of anonymity to talk candidly…

One Trump loyalist — noting that Corker has many more friends in the Senate than Trump does — said the rift could dash chances for a tax law overhaul or other meaningful legislation. “His presidency could be doomed,” said this person, who spoke on the condition of anonymity so as not to alienate the president or his staff.

“We have been watching the slow-motion breakup of the Republican Party, and Trump is doing what he can to speed it up,” said Patrick Caddell, a veteran pollster who has worked with Stephen K. Bannon, Trump’s former chief strategist, who now runs Breitbart News, a conservative website.