Sen. Orrin Hatch filed an amicus brief earlier this month in an upcoming Supreme Court case that could have major implications for special counsel Robert Mueller's investigation into Russian interference in the 2016 election.

Hatch filed the brief in Gamble v. United States, which challenges an exception to the Fifth Amendment's double-jeopardy clause, allowing both state and federal courts to prosecute a person for the same crime. Hatch wants that loophole closed.

The Atlantic's Natasha Bertrand writes that, if the court decides the way Hatch is pushing them to, a federal pardon would block a state-level prosecution. 

Within the context of the Mueller probe, legal observers have seen the dual-sovereignty doctrine as a check on President Donald Trump’s power: It could discourage him from trying to shut down the Mueller investigation or pardon anyone caught up in the probe, because the pardon wouldn’t be applied to state charges. Under settled law, if Trump were to pardon his former campaign chairman Paul Manafort, for example—he was convicted last month in federal court on eight counts of tax and bank fraud—both New York and Virginia state prosecutors could still charge him for any crimes that violated their respective laws. (Both states have a double-jeopardy law that bars secondary state prosecutions for committing “the same act,” but there are important exceptions, as the Fordham University School of Law professor Jed Shugerman has noted.) If the dual-sovereignty doctrine were tossed, as Hatch wants, then Trump’s pardon could theoretically protect Manafort from state action.

 

If Trump were to shut down the investigation or pardon his associates, “the escape hatch, then, is for cases to be farmed out or picked up by state-level attorneys general, who cannot be shut down by Trump and who generally—but with some existing limits—can charge state crimes even after a federal pardon,” explained Elie Honig, a former assistant U.S. attorney in New Jersey. 

 

A spokesman for the senator denied that his brief was inspired by the Mueller investigation, noting that Hatch has “worked for years to address the problem of overcriminalization in our federal code” and wants the Court “to reconsider the rationale” for the doctrine “in light of the rapid expansion of both the scope and substance of modern federal criminal law.”

The Gamble case is not related to the Muller investigation.