Rep. Marjorie Taylor Greene (R-Ga.) on Friday introduced a motion to vacate against House Speaker Mike Johnson (R-La.), threatening a future vote to oust him.

Why it matters: Greene isn't yet forcing the vote to remove Johnson as speaker — but the move lays the groundwork for another historic showdown on the House floor.

• Johnson's predecessor, Rep. Kevin McCarthy (R-Calif.), became the first House speaker to be ousted after hardline Republicans triggered a motion to vacate against him last year.
• Greene said she would bring the vote to remove Johnson if he attempts to pass Ukraine aid, which she and other hardline Republicans fervently oppose.

What they're saying: "I filed a motion to vacate today, but it's more of a warning than a pink slip," Greene told reporters on the Capitol steps.

• "I do not wish to inflict pain on our conference and throw the House in chaos, but this is basically a warning," she continued, noting she has not imposed a "time limit" on the vote.
• "It's time for us to go through the process, take our time and find a new speaker of the House that will stand with Republicans and our Republican majority, instead of standing with the Democrats."

The other side: "Speaker Johnson always listens to the concerns of members, but is focused on governing," Johnson spokesperson Raj Shah told Axios.

• "He will continue to push conservative legislation that secures our border, strengthens our national defense and demonstrates how we'll grow our majority."
• A House official told Axios that because Greene didn't file a privileged motion, the measure cannot be considered until after the House's two-week recess.

Zoom in: Greene's fellow hardliners told Axios she did not loop them in on her plans — though some expressed sympathy toward her underlying sentiments.

• Rep. Tim Burchett (R-Tenn.), who voted to remove McCarthy, told reporters his vote on removing Johnson is "currently no," but said Greene is "upset and concerned and has every right to be."
• "Hopefully it sparks, at the very minimum, some conversations," said Rep. Eric Burlison (R-Mo.). "We need to go back into the room and set some parameters on what our expectations are for the rest of the year ... I'm sure we'll have some meetings."

Yes, but: Some members of the right-wing Freedom Caucus — a group Greene was kicked out of last year — are skeptical, despite their criticism of Johnson.

• One member of the group said on the condition of anonymity, "I have no comment on anything she does or says. I suspect she's doing it so you all will talk about it ... so she gets the attention, which, obviously, is working."
• "I don't think many Republicans take her seriously," the lawmaker added.

What to watch: While Democrats unanimously voted to remove McCarthy as speaker in October, several indicated Friday that they would back Johnson in order to maintain stability in the House.

Axios' Juliegrace Brufke and Stephen Neukam contributed reporting.