WASHINGTON — Speaker Paul D. Ryan was re-elected to another term by the House on Tuesday, retaining the gavel as Republicans prepared to reverse reams of Obama administration policies in an era of unified Republican government.

For Mr. Ryan, 46, the vote was a formality, affirming his role as the steward of conservative policy making in the age of President-elect Donald J. Trump. Long considered the party’s intellectual core, Mr. Ryan has strained at times to corral the disparate forces in his conference, particularly hard-line members who had fought often with his predecessor, John A. Boehner.

Mr. Trump’s election has, at least temporarily, papered over any major divisions, leaving members ecstatic at the prospect of enacting proposals that stood no chance of passage with a Democrat in the White House.