Federal prosecutors have often relied on a powerful criminal statute to bring high-profile corruption cases, including the college admissions scandal that ensnared Hollywood celebrities and a string of bribery investigations that targeted college basketball programs.

But now, a key theory of that statute could be gutted because of a challenge by two defendants in another well-known case — “Bridgegate,” the September 2013 closing of access lanes to the George Washington Bridge, which connects Manhattan and New Jersey, to punish a mayor for refusing to offer a campaign endorsement.

The United States Supreme Court, in a decision that surprised legal experts, last week agreed to hear an appeal of the defendants’ corruption convictions in a move that could significantly weaken the ability of prosecutors to go after what they determine to be political malfeasance.

The court’s decision to take on the appeal by the defendants, Bridget Anne Kelly and Bill Baroni, suggests that the justices are open to overturning their convictions, legal experts said, and follows other rulings that have chipped away at federal corruption laws.