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(CNN) — Kevin McCarthy has for now lost the House speaker’s gavel in an historic moment on the heels of a showdown on Capitol Hill over government funding.

The California Republican, who was up against major challenges, including tough vote math and a conservative revolt against his speakership, was ousted in a 216-210 vote, with eight Republicans voting to remove McCarthy from the post.

House Republicans control only a narrow majority, a dynamic that has left McCarthy with little room to maneuver and has given hardline conservatives outsized influence to exert pressure over the speaker.

To win over critics and secure the speaker’s gavel in January, McCarthy and his allies made a series of concessions to conservatives. One major concession was to restore the ability of any one member to offer what’s known as a motion to vacate the speaker’s chair – a move that can trigger a House floor vote to oust the speaker.

Tuesday’s vote for McCarthy’s ouster came after firebrand Rep. Matt Gaetz, a Florida Republican, offered a motion to vacate the chair on the House floor. Here’s what that means:

What is a motion to vacate?

In practical terms, a motion to vacate the chair takes the form of a resolution to remove the speaker by declaring the speakership to be vacant. It is a rarely used procedural tool – and no other House speaker has ever been ousted through the passage of a resolution to remove them. But threats over its use can be a powerful way to apply pressure to a speaker.

How does an effort to oust the speaker unfold?

Any member can file a House resolution to remove the speaker, as Gaetz did.

According to House precedent, a resolution to remove the speaker would be considered privileged, a designation that gives it priority over other issues. But simply filing the resolution does not force a vote on its own, though it would be sure to ignite a political firestorm and a debate over the speaker’s future.

To force a vote, a member would need to come to the House floor and announce their intent to offer the resolution to remove the speaker. Doing that would then require the speaker to put the resolution on the legislative schedule within two legislative days – setting up a showdown on the floor over the issue.

If a member introduces a resolution, but does not announce it from the floor, that would not force a vote or have any immediate impact – making it more of a symbolic threat or warning shot to the speaker.

How many votes are needed?

A vote on the resolution to remove the speaker would require a majority vote to succeed and oust the speaker from their leadership post.

A vote on a resolution to remove the speaker could still be preempted, however, even once it is on track to come to the floor for consideration.

For example, when the resolution is called up on the floor, a motion to table – or kill – the resolution could be offered and would be voted on first. That vote would also only require a simple majority to succeed – and if it did succeed then there would not be a vote directly on the resolution to remove the speaker because the resolution would instead be tabled.

What happens when it succeeds?

According to the reference guide “House Practice: A Guide to the Rules, Precedents and Procedures of the House,” the speaker is required to submit a confidential list to the Clerk of people “in the order in which each shall act as Speaker pro tempore in the case of a vacancy.”

With McCarthy removed as House speaker, for now, the clerk pulls out that list, and the number one name on that list becomes the interim speaker. His or her first order of business: The election of a new speaker – and once again, the House will have to vote as many times as it takes to get someone to 218 votes, or a majority of those present and voting for a speaker.

GOP Rep. Patrick McHenry, a top McCarthy ally, was named interim speaker.

Has this happened before?

The last time a high-profile showdown played out on Capitol Hill over a motion to vacate was in 2015 when then-GOP Rep. Mark Meadows of North Carolina filed a resolution to declare the office of speaker vacant while John Boehner, an Ohio Republican, was serving as speaker. It was not brought to a floor vote, however.

Not long after the resolution was filed, Boehner downplayed its significance, calling it “no big deal.” But a few months later, he announced that he had decided to resign, saying that he had planned to step down at the end of the year but that turmoil within his caucus prompted him to resign earlier than planned.

Another notable incident took place in 1910, when then-House Speaker Joseph Cannon, an Illinois Republican, held onto the speakership after a resolution to remove the speaker came to a vote on the House floor and failed – 155 to 192.

There are a number of factors that make removing a speaker challenging.

“It’s probably harder to remove a speaker using a privileged resolution than people think,” said Matthew Green, a professor of politics at Catholic University in Washington, DC, and author of the book “The Speaker of the House: A Study of Leadership.”

“It requires a pivotal bloc of members of the majority willing to withstand criticism and peer pressure from their partisan colleagues for introducing the resolution, bipartisan agreement that the incumbent speaker should be ousted, and a majority willing to select someone else to replace the speaker.”

“It remains a potent threat as long as people believe it is a viable tool to remove a speaker. If it is actually brought to the floor and fails, it will lose its potency,” Green said.