Supreme Court Justice Amy Coney Barrett is once again facing fierce backlash from President Donald Trump’s political base after joining Chief Justice John Roberts and the court’s three liberal justices on Monday in a ruling that dealt a setback to Republican efforts to prevent states from counting mail-in ballots that arrive days or weeks after election night.

The 5-4 decision in Watson v. Republican National Committee upheld a Mississippi law allowing absentee ballots postmarked by election day to be counted if they arrive afterward, rejecting the Republican National Committee’s argument that federal law requires all ballots to be received by election day.