*Correction appended. 

Just weeks after resigning as mayor of Rio Grande City, Republican Ruben Villarreal has his sights set on Congress.

Villarreal, who was the border city's mayor of seven years, confirmed to The Texas Tribune on Sunday that he will challenge longtime incumbent U.S. Rep. Rubén Hinojosa, Democrat of Edinburg, in 2016.

“I’m prepared for whatever the role requires,” Villarreal said, adding that he made the decision after spending several weeks on the road throughout the 15th Congressional District. “... I’m walking into this process with my eyes wide open.”

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Hinojosa did not immediately respond to a request for comment.

Villarreal was first elected mayor in 2001, holding a post that once belonged to his father. He has spent his entire life on the border, where he owns his family’s auto shop.

After becoming one of the most visible surrogates on Gov. Greg Abbott's 2014 campaign, Villarreal made headlines last year when he came out as a Republican in one of the bluest parts of the state.

His bid for Texas’ CD-15 could be an uphill battle. The district stretches from deep in the Rio Grande Valley, including cities like Edinburg and McAllen, up to Seguin and parts of New Braunfels. Hinojosa has held the seat since 1996, winning his last re-election in 2014 with 54 percent of the vote.

CD-15 has leaned heavily Democratic in presidential election years; in 2012, Hinojosa won with an even wider margin of victory — 60 percent of the vote. President Obama carried the district by 16 points in 2008 and 2012.

Flipping the seat would be major coup for the GOP, which is looking to bolster its appeal to Hispanic voters. All but one of Texas' Hispanic members of the U.S. House are Democrats. But Villarreal said his campaign could contribute to the changing face of the Republican Party.

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“A ‘Republican,’ I believe, is being defined as we speak,” Villarreal said. “And I think the process that I’m going through is going to help form the definition of what a real Republican is.”

Hinojosa has also picked up a primary challenger in Mission police officer Paul Williams, who announced his candidacy last week.

Villarreal could face questions about his residency in his bid for CD-15, which doesn’t cover his longtime home base of Rio Grande City. Soon after resigning as mayor in late March, Villarreal said he moved to Edinburg “on a permanent basis.”

“By no means do I not feel like I’m not from there," he said. "I’m from a region called the Rio Grande Valley.”

Correction: A previous version of this story said all of the Hispanic Texans in the U.S. House were Democrats. There is one Hispanic Republican — U.S. Rep. Bill Flores. And Villarreal has been mayor for seven years, not 14 years as an earlier version of this story said.