Some point to a "Bradley effect" suggesting that voters are hiding their true feelings from pollsters because of Obama's race, while others say the Bradley effect either never existed or no longer exists. People who think there is a Bradley effect believe that the substantial majority of undecideds are likely to vote for McCain, enabling him to close some of the gap.
McCain should win a larger share of undecided voters than Obama, but it has little to do with race.
With Obama outspending McCain by upwards of 4 to 1, getting enormous traction with newspaper editorial boards, generating the enthusiasm to bring out crowds measured in the tens of thousands, and with Palin treated as more of a punch line than a candidate by the press--it seems likely that if voters are not ready to tell a pollster that they are with Obama, they are unlikely to get there.
But the phenomenon of undecided voters' breaking for McCain need not be called the "Bradley effect." Call it the "Bloomberg effect"--where after $100 million of spending, his mayoral challenger was able to capture essentially all of the 10 point undecided vote. Or call it the "Clinton effect"--where almost all the undecided vote swung away from the popular incumbent and went to Bob Dole. Or call it the "Reagan effect" where even during the Republican 1980 primaries, voters were apparently reluctant to say they were going to vote for the "elderly washed up actor" and he got the preponderance of the undecided vote.They all amount to essentially the same pattern. Call it "the Social Effect." Where there is a perception that there is a "socially acceptable" choice, respondents who do not articulate it, are likely not to agree with it. Are they lying? Or just genuinely torn about taking that route or another? I am not going to psychoanalyze what is going on in their heads, but in the end, the pattern tends to be that those undecided voters vote against that "socially acceptable" choice.
I would add a couple of things to his theory. Let's face it, outside of Reagan, republicans have not exactly had some of the most electrifying nominees for, say, the past 40 years.
With that said, let's take McCain in 2008. Most die hard republicans hate McCain because, well, he's a democrat. I wouldn't be surprised if a number of republicans, when polled, said they are undecided waiting to see McCain's next move and/or to show their disapproval of his past sins.
As a result, there's bound to be a flirtation with polling for another candidate or as "undecided". But when push comes to shove and the race gets serious, people start to migrate to the serious candidate; in this case McCain.
On the flip side, democrats have a bad case of Bush Derangement Syndrome. They have absolutely no indecision about the candidate who is not Bush and the polling reflects that.
I believe it's why you see democrats always tracking big in the summer and republicans always closing well.
I could be wrong but the fact that there hasn't been a democrat get 51% of the vote since LBJ in 1964 tells me I'm on the right track.