WASHINGTON — They have spent almost two years battling the establishment wing of their own party, emerging from the Republican fringes to stymie routine legislation and ignite the spark that immolated their party’s most powerful elected leader, Speaker John A. Boehner.

But in a twist that could alter the dynamics of the next Congress, these anti-establishment Republicans, known as the House Freedom Caucus, could find their influence crippled by the ascension of an anti-establishment figure to the White House.

The delirious aftermath of Donald J. Trump’s surprise election victory has, at least for now, erased the party divisions that the Freedom Caucus has leveraged within a historically unpopular Congress. After having braced themselves for a Democratic-controlled White House and Senate, Republicans are now rushing to dust off their wish lists.

“It has been roses and sunshine. It’s unbelievable,” said Representative Tom Cole, Republican of Oklahoma. “It is just amazing what a difference the Trump victory has made.”