Cuellar, a moderate Democrat, is one of two Democrats representing a South Texas district won by Trump last November and is viewed as perhaps the most vulnerable incumbent. Cuellar won reelection by more than five points—but Trump won the former Democratic stronghold by about seven points.

Texas state Rep. James Talarico (D) accused President Trump and the Republican Party of trying to “rig” elections in the state with their plan to conduct a middecade redistricting to increase the number of GOP-held seats.

Texas Democrats on Friday traveled to California and Illinois for meetings with Democratic governors who have criticized Republicans' plans to redraw the Texas congressional map to protect the GOP House majority.