*Editor's note: This story has been updated throughout.

The controversial chairman of the Travis County Republican Party has given up his post by running for president as a write-in candidate, Texas GOP officials said Thursday, signaling the end of the Robert Morrow era in the state's fifth-largest county. 

Morrow, an Austin resident who got the job in a surprise election earlier this year, appears to have forced his own resignation by filing to run — and successfully getting on the ballot — as a write-in choice. Under state law, the county chair of a political party is not allowed to also be a candidate for federal, state or county office, or even apply to be a candidate.

Prospective write-in candidates had faced a Monday deadline to submit 38 signatures to appear on the November ballot. Alicia Pierce, a spokeswoman for the Texas secretary of state’s office, said Thursday morning that Morrow met the threshold. Meanwhile, Evan McMullin, an independent candidate who has been making an effort at ballot access across the country, had his application rejected.

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In a statement Thursday afternoon, state GOP Chairman Tom Mechler said Morrow "became ineligible to hold the office of Travis County Republican Chair" upon filing Friday to be a write-in candidate. Morrow told The Texas Tribune earlier Thursday he could not be ousted.

"They don’t have the grounds to do that, and anybody who says so is probably lying," Morrow said. "The case law on this is probably extremely thin." 

Morrow has brought national notoriety to the Travis County GOP through his steady stream of tweets alleging conspiracy theories involving Democratic and Republican officials, including GOP presidential nominee Donald Trump. Morrow camped out outside events Trump held Tuesday in Austin, wearing his trademark jester's hat and holding a large sign reading, "Trump is a Child Rapist."

On Thursday, Morrow suggested county party officials were trying to oust him because he had "embarrassed the living fuck out of Donald Trump" in recent days. 

County party leaders had previously moved to limit Morrow's powers, creating a steering committee that assumed many of the responsibilities usually handled by the chairman. On Thursday morning, however, it looked like the party was preparing for further change, calling a news conference for Friday morning to "make an important announcement ... involving the future of the local GOP." Announcing the news conference, the party referred to its executive vice chairman, David Duncan, as its "acting chairman." 

A party spokesman declined to elaborate on the announcement, but a person close to the party said the news conference will likely be about Morrow's fate. It was not immediately clear how the process of Morrow stepping down would unfold, and at least one party official cautioned that the party was still conferring over the issue.

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The county party nonetheless has the support of Mechler. 

"There is absolutely no place for rhetoric as distasteful as Mr. Morrow’s in the Republican Party of Texas," Mechler said in the statement. "We are excited to move forward with the Travis County GOP and the new incoming Chair as soon as an election is held to fill the position."

The bombastic Morrow fired back on Twitter by asking Mechler to perform a sex act on him. Morrow remained defiant as speculation built Thursday afternoon that an effort was afoot to see him out as chairman. 

“If other people attempt to pull a coup like this, there will be trouble," Morrow added. "The bottom line is the Texas voters, the Republican Party, have spoken."

Morrow was elected chairman in March with 54 percent of the vote, unseating incumbent James Dickey. He quickly built a reputation for his conspiracy theories — which accuse politicians living and dead of adultery, murder and pedophilia — his lewd denunciations and his outlandish public appearances.

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