AUSTIN, Texas (AP) — Texas Gov. Greg Abbott said Wednesday that he will use $250 million in state money and crowdsourced financing to build more barriers along the U.S. border with Mexico, part of an emerging proposal that also extends his political fight over immigration with the Democratic Biden administration.

But questions remain over how far Abbott, a Republican, can go for a project whose total cost, length and timeline are unclear and could face legal challenges from the federal government.

Over a dozen Republican members of the Texas House and Senate joined Abbott for a livestreamed pr...