A longtime Democratic lawmaker from South Texas switched parties Monday, giving Republicans another boost in their aggressive attempts to make inroads with voters along the U.S.-Mexico border.

State Rep. Ryan Guillen has been one of the most conservative Democrats in the Texas House of Representatives since 2002. His switch to the GOP comes after his rural border district was redrawn to heavily favor Republicans under new maps signed in October by Republican Gov. Greg Abbott.

Guillen said his values no longer aligned with Democrats, who criticized him for switching rather than staying in the party and fighting for his seat.

The Texas border has long been a stronghold for Democrats. But the GOP is now looking to expand their reach along the border after former President Donald Trump made unexpected gains there in 2020.

(AP)