Are Democrats reluctant to tell pollsters that they approve of Trump?

There’s an idea in polling called the Bradley effect, which posits that polls misjudged Tom Bradley’s 1982 loss in California’s governor’s race because poll respondents were unwilling to admit that they planned to vote against the first black gubernatorial candidate in the state’s history. The idea, in other words, is that social pressure can shift what people will tell pollsters. CONT.

Philip Bump, Washington Post