Arizona Democratic Rep. Ruben Gallego released a video Monday announcing his intention to run for U.S. Senate in 2024, setting up a possible faceoff with Sen. Kyrsten Sinema (I-Ariz.) for her seat. The match-up could “carry high stakes for Democrats’ control of the upper chamber” since Sinema switched her party affiliation from Democrat to independent, The New York Times reports. 

Gallego, a U.S. Marine veteran who served in Iraq, kicked off his campaign with a video in which he shared his candidacy with a group of fellow veterans at American Legion Post 124 in Guadalupe, Ariz. Gallego, who is of Colombian and Mexican descent, also talked about his upbringing as the child of immigrants in Chicago and his combat experience as a Marine. If elected, he would be Arizona’s first Latino senator, per CNN. 

“You’re the first group of people that are hearing this besides my family. I will be challenging Kyrsten Sinema for the United States Senate, and I need all of your support,” Gallego told the group.

Before she left the party, Democrats criticized Sinema for opposing elements of the Biden administration’s agenda. Last year, while Sinema was still a Democrat, Gallego said some of the party’s senators were pushing him to challenge her for the seat. Sinema left the party in December but continues to caucus with Senate Democrats, per CNN. 

According to the Times, pitting Gallego and Sinema against each other in the general election will likely divide the coalition of Democrats and independents that helped secure Democratic victories in recent Arizona elections. That split could give Republicans an opportunity to snag the seat that helped Democrats narrowly maintain their Senate majority. CNN reports that Sinema has yet to announce plans to run in 2024 publicly.