The Bradley Effect is a term describing a voting phenomena which is purported to have occurred when a black candidate runs against a white candidate in a political race. In the "effect," white voters claim in advance to pollsters that they will vote for a black candidate and then end up voting for the white candidate, because they either changed their minds or initially lied to the pollster so as not to appear racist.The Washington Post: Debunking the 'Bradley Effect' (November 2, 2008)
The Bradley Effect in 2008
Some political experts have surmised that such an effect may play a role in voting during the 2008 Presidential race between Barack Obama and John McCain, and may have played a role in the 2008 Democratic primaries. However, a 2008 study suggested that the Bradley effect has been less of a factor in politics in races after 1996, and that there was no evidence of the Bradley effect in the Democratic presidential primaries of 2008.The Atlantic: Has The Wilder Effect Disappeared? (September 19, 2008)