 After months of speculation, on January 12, 2012, Marshall confirmed that he would enter the race for the Republican nomination for the U.S. Senate seat held by the retiring Jim Webb.He formally announced his candidacy on January 16, 2012, emailing supporters saying, "I can beat Tim Kaine," the presumptive Democratic nominee for the seat.He lost in the June 12, 2012, Republican primary, coming in third out of four candidates with only 7 percent of the vote.