AUSTIN, Texas (AP) — Democratic Rep. Henry Cuellar of Texas faced his first election Tuesday since his indictment on bribery charges, one of three closely watched races along the U.S.-Mexico border where Republicans are trying to widen inroads in the predominately Hispanic region.

The election is another test for Democrats in a region that has historically been a stronghold and is a recurring backdrop in the national debate over immigration.

Cuellar and his wife have pleaded not guilty to charges related to the couple's ties to the former Soviet republic of Azerbaijan. Republicans mounted an aggressive campaign in 2022 to oust Cuellar, one of his party's most outspoken moderates, but lost by double digits and pulled back in the district this year despite the indictment.

The border House districts are a competitive outlier in Texas, where Republicans have full control of the Legislature and a Democrat has not occupied a statewide office for more than 30 years.

Congressman running under indictment

Cuellar is running against Republican Jay Furman, a political newcomer and Navy veteran who is the incumbent's first challenger since being indicted on bribery charges in May.

Cuellar and his wife are accused of accepting nearly $600,000 in bribes from an Azerbaijan-controlled energy company and a bank in Mexico. The charges have given Furman room to make his case in the 28th Congressional District, where Cuellar first took office in 2005.

However, the seat has drawn less attention this cycle from the GOP than in 2022, when a multimillion-dollar challenge still ended in a decisive Cuellar victory.

A rematch in a new Texas district

Republican Rep. Monica De La Cruz is again trying to fend off a challenge from Democrat Michelle Vallejo after winning by 8 percentage points in 2022.

De La Cruz was the first Republican to win a congressional race in South Texas. The 15th Congressional District was one of two new seats awarded to Texas following the 2020 census, driven by the state's booming Hispanic population, and was drawn by Republican mapmakers to give them an edge.

Vallejo's campaign has leaned into protecting Social Security and Medicare, which are popular programs among her primarily Latino and working-class base. De La Cruz has touted her support of tougher border security policies, including those backed by former President Donald Trump.

Republicans hone in on the Rio Grande Valley

Republicans are zeroing in on Democratic Rep Vicente Gonzalez in a rematch with former Rep. Mayra Flores, who Republicans see as a rising star on the southern border.

Of the three border races in Texas, Republicans have thrown most of their muster behind their campaign to unseat Gonzalez, a moderate Democrat who defeated Flores by more than 8 percentage points in 2022.

Republican House Speaker Mike Johnson has campaigned for Flores, who was the first Mexican-born woman elected to Congress and has outraised Gonzalez in a race that is one of the GOP's biggest targets nationally. Flores previously held the seat after winning a special election earlier in 2022, under a map that was more favorable to Republicans.

Shifts in South Texas

Counties along the Texas-Mexico border made significant swings in 2020 toward Trump. The rightward shift represents a changing political landscape along the U.S.-Mexico border where border security has become a key issue for voters. President Biden won Hidalgo County, a reliably blue district, by less than half the margin that Hillary Clinton did in 2016. In rural Zapata County, Trump flipped the county altogether after Clinton won it by 33 percentage points four years prior.

The gains have led to Republicans to invest millions of dollars into what were once considered deep blue districts.

Democrats did, however, close the gap statewide in 2020 where Trump won Texas by less than 6 percentage points. It was the closest margin of victory for a GOP presidential nominee in Texas in decades.