Donald Trump will announce next week his choice to fill the Supreme Court seat of the late Justice Antonin Scalia. According to various reports, he has narrowed his choices down to a few extremely conservative white men (a shock, I know). Democrats don't have many weapons to fight this battle other than their outrage, but there's one trigger they should pull: Filibuster this nomination. It won't stop Trump's nominee from joining the Court, but it's still worth doing.

If Democrats take that step, they'll be making clear just how extraordinary the current situation is, because filibusters of Supreme Court nominees are, though not completely unprecedented, highly unusual — the last one was nearly half a century ago, when Republicans filibustered Lyndon Johnson's 1968 nomination of Abe Fortas to be chief justice.

And this nomination is extraordinary, not because of the ideological extremism of the nominee, whom at this point we can presume will be little different from the justice he'll be replacing. There will be plenty of substantive reasons for Democrats to oppose him, including the fact that he'll almost certainly be a vote to overturn Roe v. Wade. But this is an extraordinary moment because of what Republicans did to get us here.

As you'll recall, when Scalia died last February, President Obama nominated Merrick Garland, a moderate appeals court judge who had received glowing praise from many Republicans. But GOP senators decided to invent a new rule for nominees to the high court, a rule stating that when a Democrat is president, he only gets to fill Supreme Court vacancies for the first three years of his four-year term. They insisted that it was necessary to "let the people decide" who the next justice should be, even though the people decided quite clearly by electing and re-electing Obama. Republicans made a gamble that the political fallout from this unprecedented move would be minimal, and if their eventual presidential nominee won the election, they would have prevented the Court from moving to the left. It was a gamble that paid off.

But it's important that Democrats not let anyone forget just how reprehensible that move was. So no matter who President Trump nominates, every Democrat ought to say something like this:

I'm prepared to listen to any Supreme Court nominee, and there may be a qualified Republican nominee in the future whom I'll vote for. But not this time. This seat should have been filled by Merrick Garland, and I cannot in good conscience cast any vote that would affirm the inexcusable manner in which Republicans won this seat for themselves.

If Democrats do decide to filibuster, they may well succeed in stalling the nomination. They have 48 seats in the Senate, seven more than they need to sustain a filibuster, even if they lose the votes of a few senators from conservative states, like Joe Manchin of West Virginia and Heidi Heitkamp of North Dakota, who can be counted on to desert their party whenever something controversial comes up.

And we know what would happen then: Republicans would change Senate rules to disallow filibusters on Supreme Court nominations, as they've already threatened to do. Then the nominee will get a vote, and he'll be confirmed with the votes of every Republican and a few Democrats.

Which, to be honest, is fine. Before the election when everyone assumed that Hillary Clinton would win, Senate Democrats warned that they'd do the same thing if Republicans filibustered Clinton's nominee for this seat.

And maybe there shouldn't be filibusters of Supreme Court nominees, which have become much more likely now that we're in such an intensely partisan age. There was a time when nominees would routinely be approved almost unanimously; Scalia was confirmed on a 98-0 vote, while liberal Ruth Bader Ginsburg was confirmed 96-3. But that time is behind us. And you can be sure that the filibuster's days are numbered one way or another when it comes to Supreme Court nominations. If Republicans get rid of it now, Democrats will thank them the next time there's a Democratic president.

But in the meantime, a filibuster of Trump's nominee would be true to the original spirit of the filibuster, which was once used by the minority party only to register a powerful dissent in extraordinary circumstances. Well, this is an extraordinary circumstance, and Democrats have to take a stand.

This is just one of the battles they're likely to lose over the next four years, but sometimes, the way you lose matters a great deal. This is one of those times.