The death of Antonin Scalia has set off yet another epic partisan struggle as Senate Republicans seek to deny President Obama his constitutional right to nominate the next Supreme Court justice. They want to wait out Obama’s last year in office, hoping his successor will be one of their own.

If the Democrats choose Bernie Sanders as their presidential candidate, Republicans will almost certainly get their wish. Furthermore, the Republican president would probably have a Republican-majority Senate happy to approve his selection.

The makeup of senatorial races this November gives Democrats a decent chance of capturing a majority. Having the radical Sanders on the ballot would hurt them in swing states.

Some Sanders devotees will argue with conviction that these purplish Democrats are not real progressives anyway, not like our Bernie. Herein lies the Democrats’ problem.

No sophisticated pollster puts stock in current numbers showing Sanders doing well against possible Republican foes. The right has not subjected Sanders to the brutality it routinely rains on Hillary Clinton — precisely because he is the candidate they want to run a Republican against. Should Sanders become the nominee, the skies will open.

One may applaud Sanders’ denunciation of big money in politics, but a moderate Democrat in the White House could do something about it. A democratic socialist not in the White House cannot. Campaign finance reform would be a hard slog under any circumstances, but a seasoned politician who plays well with others could bring a reluctant few to her side.

Some younger liberals may not know the history of the disastrous 2000 election, where Republicans played the left for fools. Polls were showing Al Gore and George W. Bush neck-and-neck, particularly in the pivotal state of Florida.

Despite the stakes, prominent left-wing voices continued to back the third-party candidacy of Ralph Nader. You had Michael Moore bouncing on stages where he urged cheering liberals to vote for the radical Nader because there was no difference between Gore and Bush. Republicans, meanwhile, were running ads for Nader. That was no secret. It was in the papers.

When the Florida tally came in, Bush held a mere 537-vote edge. The close results prompted Florida to start a recount of the votes. Then, in a purely partisan play, the conservative majority on the Supreme Court stopped the recount, handing the election to Bush.

The bigger point is that Gore would have been the undisputed winner in 2000 had Nader not vacuumed up almost 100,000 Florida votes, most of which would have surely gone to him.

Same deal in New Hampshire, where Nader siphoned off more than 22,000 votes. Bush won there by only 7,211 ballots.

Now, Sanders is an honorable man running a straightforward campaign for the Democratic nomination. One can’t imagine his playing the third-party spoiler.

But what makes today similar to 2000 is how many on the left are so demanding of ideological purity that they’d blow the opportunity to keep the White House in Democratic hands. Of course, they don’t see it that way. This may reflect their closed circle of like-minded friends — or an illusion that others need only see the light, and their hero will sweep into the Oval Office.

The other similarity to 2000 is the scorn the believers heap on the experienced liberal alternative. They can’t accept the compromises, contradictions and occasional bad calls that attach to any politician who’s fought in the trenches.

The next president will almost certainly be either Clinton or a Republican. Democrats must ask themselves: Whom would you prefer to name future Supreme Court judges?

Froma Harrop is a syndicated columnist. Follow her on Twitter @FromaHarrop. She can be reached by email at: fharrop@gmail.com.