Reid and his caucus already nuked part of it in 2013, eliminating filibusters on presidential appointments (with the notable exception of Supreme Court appointments). The 60-vote requirement remains in place for SCOTUS nominations and of course for regular legislation. But what if it didn’t? What if the new Democratic Senate majority discovers next year that they simply can’t find 60 votes for President Clinton’s new mass amnesty bill? Do they go thermonuclear and eliminate the legislative filibuster too, reducing the Senate to a simple-majority institution?

One of the arguments #NeverTrumpers use to counter the idea that a Trump defeat would turn the Supreme Court radically left-wing is the fact that the filibuster remains in place. Hillary can’t go too radical with her nominees, the theory goes, because McConnell’s caucus will certainly have more than 41 votes next year even if they’re a minority. The flaw in that theory is that Chuck Schumer could always push the button and nuke the SCOTUS filibuster too. And, unlike with legislation, there’s nothing the Republican House could do about it. Supreme Court confirmations are a matter for the Senate alone.

High stakes here. Weird that Harry Reid would want to cut a campaign commercial for Trump by reminding Republicans who are leery of him that they could lose everything if Hillary wins.

“Unless after this election there is a dramatic change to go back to the way it used to be, the Senate will have to evolve as it has in the past,” Mr. Reid told me, referring to a former tradition of rarely mounting filibusters. “But it will evolve with a majority vote determining stuff. It is going to happen.”… “What choice would Democrats have?” asked Mr. Reid, who lamented the inability of a stalemated Congress to take on big issues. “The country can’t be run this way, where nothing gets done.”… “It’s an odd thing to say for a guy who is leading multiple filibusters at the moment,” Don Stewart, a spokesman for Senator Mitch McConnell, the Kentucky Republican and majority leader, said about Mr. Reid’s view. “Why doesn’t he start next week by ending the Democrats’ filibusters of anti-Zika funding, of veterans funding, of funding for our troops in the field?”

Reid’s headed for retirement but this calculus is obviously swirling in incoming majority leader Chuck Schumer’s head too. To nuke or not to nuke? Let’s think it through. For starters, remember that the 2018 Senate map is very favorable to the GOP. Many more Democratic incumbents are up for reelection than Republicans are, and Republicans have had amazing success in the past two midterm elections. If Schumer gets rid of the filibuster, odds are good that he and Hillary will have only two years to take advantage. Odds are also good that Republicans will hold the House this year although, depending upon how poorly Trump does at the top of the ticket, their majority might be much reduced. Even so, that factors into Schumer’s planning: Nuking the filibuster on legislation is worth doing only if Senate Republicans are the only obstacle to passing Hillary’s agenda. (Again, as noted above, the SCOTUS filibuster is a different story.) There’s no point in taking away Mitch McConnell’s ability to block Hillary if Paul Ryan can step in and block her instead. If this November is a blue landslide and the House flips, then Schumer going thermonuclear is a serious option. If the House stays red, what’s the point?

But there’s another wrinkle. If Hillary wins, it’ll mean 12 consecutive years of Democratic control of the White House. She’ll enjoy the advantage of incumbency in 2020, but the fact remains that neither party has had two different presidents elected successively to multiple terms in more than 100 years. (FDR was elected four times followed by Harry Truman being elected, very narrowly, once.) If Schumer nukes the filibuster next year, he’s staring at the possibility of a Republican majority in the Senate in 2019 and a Republican president in office in 2021 — and there’s a fair chance the House will remain Republican into the next decade. He’ll be setting a precedent by which Republicans might enjoy total control of government in the near-term with Democrats powerless in Congress to stop them. Is that worth two years of a filibuster-less Senate under President Hillary, knowing that Ryan and the House can block Democratic legislation anyway? Is it worth gambling that eliminating the filibuster for SCOTUS nominees won’t come back to haunt the left in the next decade?

I don’t think Schumer will roll the dice. The best argument you can make for doing it is that, if the left’s worst fears come to pass and the right takes over the government in the next decade, the Republican Senate majority leader will surely nuke the SCOTUS filibuster himself. Dems might as well get a jump on them. But even then, Schumer has to consider how much grief he and Hillary will want to take from the left on Supreme Court nominations if he makes confirmation a matter of a simple majority vote. (Even to a liberal like him, the left can be a pain in the ass.) For instance, it’s quite possible that President Hillary would re-nominate Merrick Garland to fill Scalia’s vacancy if the filibuster remains intact, on the theory that only a center-left nominee stands a chance at winning 60 votes. With the filibuster gone, though, the left would demand a progressive radical on the Court. Would Hillary be willing to do that at the start of her term, knowing that Republicans will use it to galvanize midterm turnout? Would Schumer want the headache of shepherding Democratic Senate votes for some ultra-far-left Court nominee knowing how vulnerable his caucus is in 2018? Preserving the filibuster for strategic reasons is a way for him and Hillary to temper expectations among Berniebros and other progressives who want to drag the party towards a more Sanders-esque socialist orientation. Clinton and Schumer might support that on the merits, but electorally? I don’t know.