 On September 16, second-place finisher Bill Thompson conceded, citing the unlikelihood of winning a runoff even if uncounted absentee and military ballots pushed de Blasio below the 40% threshold.Thompson's withdrawal made de Blasio the Democratic nominee against Republican Joe Lhota in the general election.Exit polls showed that the issue that most aided de Blasio's primary victory was his unequivocal opposition to "stop and frisk."