WASHINGTON—This week’s Senate showdown over the pending Supreme Court confirmation will go down in history because by next weekend America will either see the first ever successful partisan filibuster of a nominee or the Senate will reject using filibusters to block presidential nominations.

The Senate’s judiciary committee will vote Monday, April 3, on the nomination of Judge Neil Gorsuch to be the next justice on the U.S. Supreme Court to succeed a historic figure in American law, Justice Antonin Scalia. The committee will favorably report the nomination to the full Senate, possibly on a party-line 11-9 vote.

The full Senate will debate Gorsuch’s nomination starting Tuesday, with a final vote on Friday, April 7.

For well over a century, senators have used Senate Rule XXII to kill legislation. That rule allows that for any debatable question (meaning issue or measure) before the Senate, each senator is able to speak twice on each question in any one legislative day. A legislative day begins whenever the Senate is gaveled to order and ends whenever the presiding officer adjourns the Senate.

A filibuster occurs when a senator expects that a legislative measure he opposes might pass, so he takes all the time he can consume to keep talking about the issue to stall a final vote. If there are other senators who likewise want to defeat the measure, then when the first senator is too exhausted to talk any longer (because there are all sorts of Senate rules that burden a speaker’s ability to continue, such as the requirement that they stand rather than sit, and cannot have water or other drink on the Senate floor), one of his supporting colleague starts his own multi-hour speech, and they pass it down the chain from there.

The Senate must stay in session around the clock if it wishes to pass the measure. If at any point the Senate adjourns for the night, then when a new session begins the clock starts all over again.

The procedure for forcing an end to debate is called a cloture motion. It takes a 3/5 vote of the Senate (meaning 60 senators in the 100-member body) to invoke cloture. After that point, any additional debate is limited to 30 hours. When debate ends, the Senate holds a final vote. If 41 senators oppose cloture, the filibuster continues.

However, the Senate has two business calendars. One is legislative, where it works as the counterpart of the U.S. House to pass bills into law. The other is executive, where the Senate has a role in judicial appointments and high-level executive appointments.

Even though Senate Rule XXII does not explicitly say it applies only to legislative business, the reality is that senators never used it against judicial nominations, keeping the executive calendar to separate procedures.

Occasionally a Supreme Court nominee may be confirmed only narrowly, such as Justice Clarence Thomas, who was confirmed by a vote of 52-48. But no one attempted to filibuster the Thomas nomination. It was taken for granted that the nomination deserved an up-or-down vote.

There has only been one successful filibuster of a Supreme Court nomination when President Johnson nominated Justice Abe Fortas to become chief justice in 1968. But the opposition to Fortas was bipartisan, and it appears a majority of senators in the Democrat-controlled body would have defeated the nomination.

By contrast, in 228 years, there has never been a successful partisan filibuster of a Supreme Court nomination.

But that is what Sen. Chuck Schumer (D-NY) is attempting to do this week, declaring a new 60-vote threshold for Supreme Court nominations.

In 2003, it was a more junior Schumer who introduced filibusters of presidential nominations to lower federal courts, when he led an effort to block several of President George W. Bush’s nominees to the federal courts of appeals.

In 2013 the shoe was on the other foot, with Republican senators blocking nominees of Democratic President Barack Obama to those same appellate courts. Sen. Harry Reid (D-NV) then engineered a ruling from the Senate’s presiding officer that Rule XXII does not apply to federal judicial nominees at the appellate or trial levels, or executive appointments as well, for that matter. But that ruling did not cover the Supreme Court.

There are 52 Republicans and 48 Democrats (including Independents who caucus with the Democrats) in the Senate today. Consequently, it would take eight Democrats to cross the aisle to invoke a 60-vote cloture.

If there are not eight to be found, then Sen. Mitch McConnell (R-KY) is prepared to have the chair issue a ruling that the precedent Reid created in 2013 applies to Supreme Court nominations as well. If at least 50 senators agree (because Vice President Mike Pence casts the tie-breaking vote if the Senate splits 50-50), then Gorsuch’s nomination—and all future Supreme Court nominations—will need only 51 votes. Such a ruling is called the “constitutional option” by its supporters.

This constitutional option would restore two centuries of precedent, whereby elections have consequences. The Constitution vests the power to appoint judges jointly in the president and the Senate. If the American people give the White House and the Senate to the same political party, then that party should be able to confirm its own nominees to the judiciary.

It is unclear at that point where the votes are, both on the Gorsuch filibuster and on the constitutional option. But whichever way the showdown goes, Friday’s vote will be one for the history books.

Ken Klukowski is senior legal editor for Breitbart News. Follow him on Twitter @kenklukowski.