The U.S. Supreme Court on Monday reaffirmed a 170-year-old exception to the Constitution’s double-jeopardy clause, and left the door open for state prosecutors to prosecute Trump campaign officials regardless of whether federal officials have already done so. The case, Gamble v. United States, has drawn attention for its potential effect on Special Counsel Robert Mueller’s federal prosecutions on Russian interference in the 2016 election. Had the “dual sovereignty doctrine” been repealed, states would not be able to pursue investigations parallel to the federal government, the National Law Journal reports. State prosecutors in New York have brought charges against former Trump campaign chairman Paul Manafort Jr., who was sentenced to seven and a half years in prison, in the event that President Trump pardons him.

In the 7-2 majority decision, Justice Samuel Alito Jr. wrote that the separate sovereigns exception “honors the substantive differences between the interests that two sovereigns can have in punishing the same act.”