Debate began Tuesday afternoon on the motion to vacate ahead of the vote on it. Gaetz ceded the floor to Virginia Republican Rep. Bob Good.

"Like so many others, I deeply regret that we are here in a totally avoidable situation," Good said as he began his remarks, which largely targeted McCarthy's actions on spending to date. "I must take you back to January, however, which for many of us was about not repeating the failures of the past and letting Republican voters across the country down once again."

Good continued, "Back in January, I expressed my concern that the previous two years during my first term here in this House, we had not used every tool at our disposal to fight against the harmful, radical, Democratic agenda that is destroying the country, bankrupting the country and under which the American people are suffering."

The motion to table Gaetz's own motion to vacate -- which would have effectively killed his request before it received a vote -- has failed, 208-218.

Eleven Republicans joined all Democrats in voting it down -- setting up a key vote on the motion to vacate.

The failure of the motion to table suggests McCarthy's speakership is in real jeopardy as he would need a majority of support of the chamber to back him in order to keep his role.

A vote on the motion to vacate is expected shortly. After the vote, McCarthy slumped in his chair in the second row.

-ABC News' Adam Carlson

From the moment McCarthy was elected speaker, it was clear that his ability to keep that job could depend on Democrats.

To get elected on that 15th ballot in January, McCarthy had to agree to a series of rules that made him a profoundly weak speaker -- including the provision allowing a single member of the House to call for a vote to oust him (the now-famous "motion to vacate"). But while it takes just one member to call for such a vote, it requires a majority to actually remove the speaker.

McCarthy could survive a rebellion from a handful of renegade Republicans -- but he could not survive such a rebellion if Democrats go along with it.

Gaetz has said he expected Democrats to save McCarthy. Many others did too.

As recently as Tuesday morning, House Minority Leader Hakeem Jeffries suggested a way out of this for McCarthy. In an interview on MSNBC, he said House rules should be changed so that a single member could not force a vote on removing the speaker. Jeffries could deliver the votes to save McCarthy's job and the votes to change the rules to make it impossible for Gaetz to pull off a stunt like this again.

But Democrats would have a price for doing that. What would McCarthy offer in return? An end to the impeachment inquiry in President Joe Biden and his family? A guarantee that McCarthy honors the deal he struck on spending with the White House? Power sharing?

McCarthy has developed a cordial relationship with Jeffries, but he signaled no willingness to give Democrats anything in exchange for keeping the job.

In fact, McCarthy's actions have made it virtually impossible for Jeffries to throw him a lifeline. The speaker unilaterally launched the impeachment inquiry and just Saturday infuriated Jeffries by attempting to jam Democrats on a bill to keep the government funded for 45 days.

Back in January -- and again last month on impeachment -- McCarthy showed he was willing to do almost anything to appease his right-wing critics to get and keep his job. That worked for a while -- but it has made it virtually impossible to get Democrats to save him now.

-ABC News Chief Washington Correspondent Jonathan Karl

McCarthy ally Rep. Tom Cole, R-Okla., introduced a motion to table -- or effectively kill -- Gaetz's effort to oust McCarthy.

Democrats then requested a voice vote on the motion, which is ongoing. It is a 15-minute vote.

Now-former Speaker McCarthy addressed reporters from Capitol Hill on Tuesday night where he looked back at his years in Republican leadership, touted his record -- and struck an optimistic if ambiguous note about his future.

"I believe I can continue to fight," McCarthy said, while noting that he will not run again for speaker after he lost a historic vote on the motion to vacate earlier in the day.

"My goals have not changed. My ability to fight is just in a different form," he said, later adding, "I'll never give up on the American people. That doesn't mean I have to be speaker."

McCarthy also swiped at the conservative rebels who ousted him from his role -- stressing that they were just 4% of the GOP conference -- and claimed that Gaetz was acting out of a personal sense of grievance in pushing him out, which Gaetz denies.

Despite the defeat he suffered from within his own party, McCarthy sounded largely sanguine about his political career.

He contended that the Democratic minority deciding to vote against him had made a "political decision" that undercut the ability of the House to govern.

"My fear is the institution fell today," he said.

Still, in largely valedictory remarks, he pointed back to work to cut government spending, expand his party's base and increase their majority in Congress, including by electing more women and minorities.

"I feel fortunate to have served the American people," he insisted. "I leave the speakership with a sense of pride, accomplishment and, yes, optimism."

-ABC News' Adam Carlson