But all of those plans will play out in an election year that is shaping up as a referendum on Mr. Trump.
“Hope springs eternal, but they’d have to be a real reversal from the way they’ve operated now,” said Senator Chuck Schumer of New York, the Democratic leader.
Mr. McConnell declared 2017 a year of “extraordinary accomplishment,” a boast that only weeks ago seemed impossible. But a year marred by public spats between the president and Republican leaders in Congress was capped off with a rewrite of the tax code that cut corporate tax rates, favored business owners and reduced income tax rates, at least temporarily, for most families. The same law opened Alaska’s Arctic National Wildlife Refuge to oil exploration, a goal sought by Republicans for decades.