In 2018, Canseco contested the District 21 U.S. House seat vacated by the retiring Republican Lamar Smith. He finished in a multi-candidate field with 4 percent of the ballots cast.<ref>Texas Secretary of State, Republican primary election returns, March 6, 2018.</ref> [[Chip Roy]], who carried the backing of U.S. Senator [[Ted Cruz]], narrowly won the Republican runoff contest and then the general election on November 6, 2018. | In 2018, Canseco contested the District 21 U.S. House seat vacated by the retiring Republican Lamar Smith. He finished in a multi-candidate field with 4 percent of the ballots cast.<ref>Texas Secretary of State, Republican primary election returns, March 6, 2018.</ref> [[Chip Roy]], who carried the backing of U.S. Senator [[Ted Cruz]], narrowly won the Republican runoff contest and then the general election on November 6, 2018. |