When a voter says one thing to an election pollster and then does another thing in the anonymity of the voting booth, it is called a curious flip-flop.

But when one candidate is black and the other is white, and the results don’t reflect polls favoring the black contender, it is called the Bradley Effect.

The tag comes from the 1982 California governor’s race when polls showed Democrat Tom Bradley, the black mayor of Los Angeles, with a comfortable lead over Republican George Deukmejian right up to election day. When the votes were counted, Deukmejian won by a narrow margin.

Like it or not, there’s reason to believe the Bradley Effect could impact the outcome of November’s presidential election between Democrat Barack Obama and Republican John McCain.

A hint of that probability emerged in interviews last week with 36 undecided voters from eight swing states. The interviews were conducted by reporters for CNHI newspapers in Ohio, Michigan, Minnesota, Iowa, Pennsylvania, Indiana, Missouri and New Hampshire.

Ten of the 36 said the United States had not come far enough in race relations to elect an African-American to the presidency. Twenty-four respondents said race would make no difference and two did not answer the question.

The replies might not seem significant or even surprising until you do the math. More than one-fourth of the undecided said race would matter — and in a tight election, it could be the factor that determines the winner.

A recent CBS poll concluded that about 20 percent of the nation’s registered voters still haven’t made their final decision about Obama and McCain. If that’s true, undecided voters in the swing states would appear to hold the key to who becomes our next president and thus they bear watching and polling.

The problem is determining their true preference once they start embracing one candidate or the other. They might tell the pollsters they prefer Obama because of the economic crisis, and yet end up voting for McCain because of racial motivation.

Obama, whose father was from Kenya, Africa, and whose mother was white, may already have experienced the Bradley Effect in the New Hampshire presidential primary. The polls showed him with a double-digit lead over Hillary Clinton but the Democratic voters gave her the state by three points.

New Hampshire is an overwhelmingly white state with a history of conservative views on social and economic issues, although the 2006 election indicated that characterization may be out-of-date due to a steady influx of new residents from liberal Massachusetts. Democrats now occupy the governor’s office and both of the state’s U.S. House seats.

It is also entirely possible that white primary voters who told pollsters they preferred Obama decided to switch to Clinton because she waged an effective and emotional campaign in the final days of the New Hampshire contest.

Concealed racial bias among American voters has never been directly tested in a presidential election. And no matter who wins Nov. 4, we may not know for sure if it affected the outcome. Exit polls to determine the motivation for voting cannot be trusted on the question of race. Most voters with anti-black sentiments aren’t likely to admit it was a factor in who they voted for.

Most pollsters contend there’s no pre-election evidence that race could be a deciding issue in the Obama-McCain contest. They say voters are largely focused on the crippled economy and which candidate can best restore confidence and stability to the nation’s financial system.

Sandy Quarles, 72, a black Republican businessman from Kokomo, Ind., who said he's an undecided voter, certainly feels that way. He told the Kokomo Tribune the economy is in “the worst mess we’ve been in since 1929” and voter concern about it will transcend race, age and gender.