In 2008, Larson ran unsuccessfully for Texas' 23rd congressional district seat once held by the Republican Henry Bonilla of San Antonio. In the Republican primary election, Larson defeated attorney and banker Quico Canseco, formerly of Laredo, Texas. Larson then lost in the general election to incumbent Democrat Ciro Rodriguez of San Antonio in the Hispanic-majority district. The vote was 55.8 percent for Rodriguez and 41.9 percent for Larson, with the remaining ballots held by a Libertarian candidate. In 2010, Rodriguez was unseated by Canseco, who won the Republican nomination that year, but Canseco served only for one term, having been defeated in 2012 by another Democrat, Pete Gallego, a state legislator from Alpine, Texas. Gallego lost the seat in 2014 to the African-American Republican Will Hurd.