Ryan Guillen has represented South Texas's District 31 since 2003, first elected as a Democrat at age 24, one of the youngest Texans ever elected to the House.
In November 2021 Guillen switched parties and has served as a Republican since, currently chairing the House Agriculture & Livestock Committee.
Guillen’s take on Texas values
Even during his years as a Democrat, Guillen consistently voted with Republicans against abortion rights, and he has continued that position as a Republican since 2021. [Wikipedia; house.texas.gov]