The Bradley effect (less commonly the Wilder effect) is a theory concerning observed discrepancies between voter opinion polls and election outcomes in some United States government elections where a white candidate and a non-white candidate run against each other. The theory proposes that some voters who intend to vote for the white candidate would nonetheless tell pollsters that they are undecided or likely to vote for the non-white candidate. It was named after Los Angeles Mayor Tom Bradley, an African-American who lost the 1982 California governor's race despite being ahead in voter polls going into the elections.
"Good" Republicans ashamed to admit that they'd vote for Trump? Too ashamed to admit it even to anonymous polls?