Sen. Jeff Merkley (D-Ore.) gave a marathon speech on the Senate floor against Supreme Court nominee Neil Gorsuch, starting the evening of April 4, and into the morning of April 5. (U.S. Senate)

Mostly while we slept Tuesday night, Sen. Jeff Merkley (D-Ore.) seized the Senate floor for roughly 15 hours in an attempt to launch an old-school filibuster to block Judge Neil Gorsuch from getting on the Supreme Court. He ended it around 10:30 a.m. Wednesday morning.

But his filibuster came too late to be able to derail or even delay Gorsuch's confirmation. In fact, it probably wasn't even technically be a filibuster. That's because procedurally, there's nothing he nor his colleagues can do to stop Gorsuch from getting a vote on Thursday to advance his nomination — and, ultimately, not much they can do stop him from getting on the court.

To understand why, we first have to understand the most accepted definition of a traditional filibuster. The Senate has no limits on how long a senator can talk. And once a senator gets talking, they usually cannot be interrupted or cede the floor without their consent. So, if this were a traditional filibuster, it means as long as Merkley (and other senators who join him) talk, they can hold up the Senate procedure.

Filibustering has been around for more than a century as a last-ditch obstruction tool for senators to stop or delay legislation. Here are five of the most memorable ones. (Jenny Starrs/The Washington Post)

“Conducting a filibuster by extended debate is potentially straightforward, although it can be physically demanding,” reads a 2014 report by the nonpartisan Congressional Research Service. “A senator seeks recognition and, once recognized, speaks at length.”

Except there is one thing that can force a talking senator to yield the floor. And it's the one thing Senate Majority Leader Mitch McConnell (R-Ky.) set in place Tuesday: A vote to end debate on Gorsuch.

There aren't many rules on how long a senator can talk, but there are tons of rules about how long senators have to wait to vote. For example, McConnell knew his colleagues in the minority were going to filibuster Gorsuch — either by actually talking, like Merkley is, or threatening to talk, like Senate Minority Leader Chuck Schumer (D-N.Y.) has. So before anything began, McConnell filed a motion to vote to end that debate. That motion, called a cloture motion, has to wait two days before it is “ripened” and senators can actually vote on it.

McConnell started the clock Tuesday on Gorsuch's nomination. By Thursday, it will be time to take a vote on whether to end debate on Gorsuch. And taking a vote on Gorsuch is the one thing in Senate rules that could have interrupted Merkley from his marathon speech — assuming he and his colleagues were still talking by that point. (The longest filibuster in history is widely considered to be the late senator Strom Thurmond of South Carolina, who held up the Senate floor for 24 hours and 18 minutes in 1957 to delay the Civil Rights Act.)

The Congressional Research Service again (my emphasis in bold added):

“One hour after the Senate convenes on the day the cloture motion has ripened or matured, the presiding officer interrupts the proceedings of the Senate, regardless of what is under consideration at the time, and presents the cloture motion to the Senate for a vote.”

The vote Thursday will be a critical one for Gorsuch. His nomination is not expected to clear the 60-vote hurdle, thanks to nearly all Senate Democrats expected to vote against advancing his nomination.

(The Washington Post)

I outline what happens after that vote here and why it won't stop Senate Republicans from putting President Trump's nominee on the Supreme Court. Short answer: Once that vote fails, Republicans will likely start a process to lower the threshold for ending debate from 60 votes to a simple majority, effectively killing the filibuster for Supreme Court nominees.

Because of this cloture rule that can interrupt any talking senator, Cornell Law University Professor Josh Chafetz says most filibusters over the past decade haven't been filibusters in the true sense of being able to hold up Senate procedure — think of Sen. Ted Cruz's (R-Texas) 21-hour speech in 2013 ahead of a government shutdown. He ended the speech just as the Senate was about to vote on a spending bill. But if he had been talking, the vote that would have ended his speech for him.

The purpose of a traditional filibuster can be twofold: To try to convince other senators of your point, or to delay proceedings.

So what's the purpose of talking when you know you're not able to actually delay anything? Well, Merkley's got us writing about him — and you reading about him — doesn't he? From the perspective of a senator who's got something to say, that's probably worth staying up all night for.

This post has been updated.