As Republicans last week came up short yet again in their push to repeal the Affordable Care Act — a health care law that she was instrumental in writing and enacting as speaker of the House — Ms. Pelosi feels she is taking good advantage of the place she retained at the negotiating table. By virtue of Democratic unity and Republican disarray, she said, Democrats have been able to shape spending bills to their liking (no border wall, for instance) and hold off Republicans on their attempts to unravel the health care law.

“That’s another reason I stayed — to protect the Affordable Care Act,” Ms. Pelosi said.

“We didn’t win the elections, but we’ve won every fight,” she said about the legislative agenda. “We’ve won every fight on the omnibus spending bill — you know the appropriations bills and the rest. You look at everything, they have no victories!”

In her post as House minority leader, Ms. Pelosi is in the congressional leadership position that arguably has the least influence of the top four. The rules of the Senate and the power of the filibuster give the Senate minority leader significant leverage. But the House is a majority-rules institution, and the majority can roll over the opposition fairly easily, as reflected in the scores of bills the Republican-led House has passed, only to see them languish in the Senate, where Democratic votes are needed in most cases to get anywhere.

But Ms. Pelosi has been able to assert herself in talks with President Trump as part of Washington’s hottest new power couple, personally branded by Mr. Trump as “Chuck and Nancy” — as in Senator Chuck Schumer of New York, the Senate Democratic leader, and Ms. Pelosi. She does not seem to mind that Mr. Schumer comes first in the president’s depiction of them.