Paul Callan is a CNN legal analyst, a former New York homicide prosecutor and currently is "of counsel" to the New York law firm of Edelman and Edelman, PC, focusing on wrongful conviction and civil rights cases. Follow him @paulcallan . The views expressed in this commentary are his own.

(CNN) Someone in the Democratic Party should remind Sen. Chuck Schumer of the axiom that "revenge is a dish best served cold," because their Senate leader is preparing a piping hot bowl of it in his veiled threat to block consideration of any of Donald Trump's Supreme Court nominees indefinitely.

The remarks are clearly meant as an aggressive counterstrike against Republicans who refused to even allow a vote on President Barack Obama's nominee, Judge Merrick Garland, who the President submitted for Senate approval last March after the death of Antonin Scalia a month earlier . But although the approach Schumer hinted at might be perfectly legal, a petulant Democratic refusal to consider and vote on Supreme Court nominees at the beginning of a newly elected president's term would violate over a century of legal precedent -- and could cause gridlock in the nation's highest court.

Schumer, speaking in an interview with MSNBC's Rachel Maddow on Tuesday, said: "It's hard for me to imagine a nominee that Donald Trump would choose that would get Republican support that we could support." Asked by Maddow whether he would do his best "to hold the seat open," Schumer responded: "Absolutely."

But while frustration over Garland's nomination might be understandable, what Schumer suggests -- leaving a Supreme Court seat open for four years -- would be unprecedented.

So far, the longest delay in filling an open Supreme Court seat occurred in the 1840s when, in August 1846, Justice Robert Grier was confirmed to the seat vacated by Justice Henry Baldwin 841 days earlier. That historic delay arose from some particularly bad blood between President John Tyler and a vengeful Whig-controlled Senate that had previously expelled Tyler from its membership ranks. The Whigs rejected all Tyler's nominees and the open seat was only filled after President James Polk took office in 1845.

Such a lengthy delay occurred during an age that makes modern-day senatorial rhetoric appear tepid. (In 1856, for example, an enraged member of the House of Representatives entered the Senate Chamber and proceeded to bludgeon Massachusetts Sen. Charles Sumner into a state of unconsciousness with a silver-tipped cane).

The longest periods a Supreme Court seat has remained unfilled over the past century have been a mere 237 and 391 days. The seat of Justice Abe Fortas remained open for 391 days until it was filled by President Richard Nixon's nominee, Justice Harry Blackmun in June 1970. The seat of Lewis Powell was finally filled by President Ronald Reagan's choice, Justice Anthony Kennedy, in February 1988.

Schumer's startling threat, if achieved, would constitute a delay of 1,460 days -- body-slamming the ancient Whig record.

So how would Schumer pull off a threat of such historic magnitude, especially since Republicans hold a majority of 52 Senate seats ? The answer is the filibuster, the ancient Senate rule that permits the blocking of a vote on a Supreme Court nomination unless 60 votes can be mustered to break the filibuster. The Democrats could theoretically gather sufficient votes to block Republicans from reaching the magic 60 vote number.

True, in 2013, the filibuster rule was sharply limited by the Democrats, who were tired of Republicans using this procedural device to block their agenda. But then-Democratic Majority Leader Harry Reid chose to retain the right of filibuster in the case of Supreme Court nominations, while prohibiting use of the procedural device in virtually all other matters. The weapon, therefore, is alive and well for upcoming SCOTUS battles.

Follow CNN Opinion Join us on Twitter and Facebook

Of course, the Republicans, if pushed to extreme anger by an intransigent Democrat minority, could invoke the so called " nuclear option " and finally put a stake through the heart of the filibuster for all time by a simple majority vote on a question of parliamentary procedure. Tradition, though, dies hard in "the world's greatest deliberative body."

The good news in all this is that until Scalia's seat is filled, life will go on, and pretty much no one except the lawyers will even notice that we have eight rather than nine justices on the Supreme Court. If the Supreme Court deadlocks 4-4 on hot button issues such as abortion, campaign financing and other points of ideological dispute, the ruling of the lower court remains intact and the business of America's courts will proceed as before.

That just leaves the question of how far Schumer and his colleagues are willing to take this. Will the Whig record for SCOTUS obstruction finally be broken? I suspect the senior senator from New York and his Senate colleagues would make a better page in the history books by avoiding obstructionism and instead confirming a justice of intellectual stature, of high ethical standards who is guided by a sense of fairness for all.