Editor’s Note: The original version of this story incorrectly stated that Republicans could use Senate rules to block a Biden Supreme Court nomination. It was based on the author’s incorrect analysis of a May 13, 2021, Congressional Research Service report. The Senate will require a majority of votes to approve Justice Stephen Breyer’s replacement, not 60 votes.

But the nuclear option can go into motion only if the Judiciary Committee reports the nomination to the floor, a procedural move that says whether a majority on the committee recommends the full Senate consider the pick. Well, in a little-noticed backroom deal that took more than a month to hammer out, McConnell and Senate Majority Leader Chuck Schumer agreed to a power-sharing plan in February that splits committee membership, staffs and budgets in half. (A full nonpartisan analysis from the Congressional Research Service regarding the current process for nominees is here.)

Why does this matter? If all 11 Republican members of the Judiciary Committee oppose Biden’s pick and all 11 Democrats back her, the nomination goes inert. (A pretty safe bet in a committee where at least half of the Republican members have White House ambitions of their own.) The nomination doesn’t die, but it does get parked until a lawmaker—historically, the Leader of the party—brings it to the floor for four hours of debate.

A majority of the Senate—51 votes, typically—can then put debate about the issue on the calendar for the next day. But that’s the last easy part. When the potential pick comes to the floor again, it’s not as a nomination. At that point, it’s a motion to discharge, a cloture motion that requires 60 votes. In other words, 10 Republicans would have to resurrect the nomination of someone already blocked in the Judiciary Committee.