Let’s get the rules out of the way first: The Senate can fill the late Ruth Bader Ginsburg’s seat on the Supreme Court as soon as President Trump nominates someone.

There’s nothing in the Constitution that prevents a Supreme Court vacancy from being filled, regardless of how close to an election it opens up.

Precedent in such a situation is different. Until Senate Majority Leader Mitch McConnell (R-Ky.) blocked President Obama’s 2016 pick eight months before the election, this hadn’t been done very often, says Russell Wheeler, an expert on Supreme Court history with the Brookings Institution.

McConnell was forging his own path, for obvious political reasons. It was a gamble that worked. President Trump won the election, Republicans kept control of the Senate, and they have since filled two Supreme Court vacancies.

McConnell has every intention of taking advantage of a vacant Supreme Court seat again, with his party in power. He issued a statement Friday night saying in part:

“Americans reelected our majority in 2016 and expanded it in 2018 because we pledged to work with President Trump and support his agenda, particularly his outstanding appointments to the federal judiciary. Once again, we will keep our promise. President Trump’s nominee will receive a vote on the floor of the United States Senate.”

McConnell can’t say he is flip-flopping on his 2016 position about election-year court vacancies because doing so benefits him politically now. So he has offered some logic that does little to disguise its political convenience: This time is different because the Senate and the presidency are held by the same party, which wasn’t the case when there was a vacancy in the last year of Obama’s presidency.

“Since the 1880s, no Senate has confirmed an opposite-party president’s Supreme Court nominee in a presidential election year,” McConnell said in his Friday statement.

Opposite-party confirmations in an election year are rare, but not necessarily for the reasons McConnell suggests. As I’ve written before, there haven’t been many cross-party Supreme Court nominations in an election year because there haven’t been that many cross-party Supreme Court vacancies in an election year. It just doesn’t happen very often, in part because Supreme Court justices typically don’t leave the bench in an election year if they can help it. (One such election-year appointment in 1956 happened smoothly because Republican Dwight Eisenhower actually nominated a liberal justice.)

Even if his argument is somewhat tortured, McConnell has been signaling his intention for a while now to move on an election-year vacancy. “Oh, we’d fill it,” McConnell said in May 2019 of an election-year vacancy, offering up the same opposite-party logic.

Procedurally, it’s easier than ever for McConnell to do this. A few years back, the Republican-controlled Senate changed the rules so that it only takes a simple, 51-vote majority to approve a Supreme Court justice. (Both parties had a hand in creating the conditions for that to happen.) Now there’s no 60-vote filibuster Democrats can use to stop the majority.

Republicans have a slim majority with 53 members. It’s hard to see any Democrats voting for this vacancy, so defections could cause McConnell trouble. And there are already signs of some.

Sen. Lisa Murkowski (R-Alaska) told Alaska Public Media earlier Friday that she would wait until after inauguration of the next president, be it Trump or Democrat Joe Biden, to uphold the argument she and Senate Republicans made so forcefully in 2016 that the people should get to decide who fills this spot.

Sen. Charles E. Grassley (R-Iowa) played a key role in holding up Obama’s nominee yet has offered hesitations about what McConnell wants to do this time. And how does Sen. Mitt Romney (Utah), the only Republican to vote to convict Trump on an impeachment count, feel about this? Sen. Susan Collins (R-Maine) is another swing vote, and she is in a tight reelection in a state that doesn’t approve of Trump.

At the same time he is preparing for a Supreme Court nomination battle, McConnell is also fighting to keep Republicans’ Senate majority.

He has vulnerable members at risk of losing their seats in Colorado, Arizona, Maine and North Carolina, and maybe even Iowa, Montana, Georgia and South Carolina. That’s a lot of states where Republicans have to play defense to keep their majority. And even before Ginsburg’s death, it was looking close.

How will those vulnerable members feel about casting such a controversial, blatantly political vote when their jobs are at stake? (Maybe not so conflicted. Some, like Sens. Martha McSally of Arizona and Joni Ernst of Iowa and Sen. Thom Tillis of North Carolina, have already said they are okay with an election-year vote.)

The politics get messier for McConnell if the process stretches on after election results are known, which it certainly could. If Biden wins and Trump loses, Trump would officially be a lame-duck president. Senate Republicans could lose their majority and be a lame-duck Senate as well.

And in 2016, McConnell actually argued against the Senate considering a lame-duck president’s nomination. “President Obama has every right to nominate someone on his way out the door,” McConnell said at the time. “The Senate has every right to hold its consent.”

It’s a lot to consider. But McConnell has the chance to thrust the Supreme Court in a more conservative direction for perhaps generations. It’s a remarkable legacy for McConnell that he doesn’t seem to want to pass up, no matter the risk for him or the Senate majority.