Inside the West Wing, aides to Mr. Trump — numbed and desensitized by breathless news cycles blaring headlines about the president’s behavior — said privately on Tuesday afternoon that they were having trouble assessing how devastating the day’s legal events might be…

“I think impeachment is now squarely going to define the midterms,” said Rob Stutzman, a Republican strategist who has been critical of Mr. Trump. “It’s inescapable now that Democrats can legitimately raise that issue.”

He added, “There’s a lot of Republican members of Congress sitting in tough districts that are going to have to really think hard about how they’re going to finesse this in the days ahead.”