WASHINGTON — For two days in January, all seemed right in the Republican Party.

Gathered in Philadelphia for their annual congressional retreat, less than a week after President Trump’s inauguration, lawmakers exulted in the possibilities of total government control, grinning through forums about an aggressive 200-day agenda that began with honoring a central campaign promise: repealing the Affordable Care Act.

Adult beverages flowed. Members were given Trump-themed socks. And the president showered praise on his most important partner, the man with the bill-writing pen, the man who would find the votes.

“Speaker Paul Ryan — very, very special,” Mr. Trump said. “He is writing his heart out, right? And we’re actually going to sign the stuff that you’re writing.”

“Now,” the president said, “it’s going to happen.”

It is not going to happen. At least not this time.