Although voters won’t be choosing which federal judges to nominate on Election Day, their determination of which party maintains dominance in Congress could make or break President Joe Biden‘s legacy of reshaping the judiciary if Republicans sweep on Tuesday.

The Senate holds the power to confirm all of the president’s federal judicial nominees up to the Supreme Court. If Senate Democrats lose their narrow 50-50 majority in the narrowly divided chamber, with Sen. Mitch McConnell (R-KY) in place to return as majority leader, Republicans would become a major roadblock to Biden’s judicial confirmations process, which amounts to 84 confirmed nominees as of Nov. 8.