PRINCETON, NJ -- While 6% of voters say they are less likely to vote for Barack Obama because of his race, 9% say they are more likely to vote for him, making the impact of his race a neutral to slightly positive factor when all voters' self-reported attitudes are taken into account. At the same time, 6% of voters say John McCain's race will make them less likely to vote for him, with 7% saying it makes them more likely to vote for him, leading to the same basic conclusion: McCain's race, like Obama's, is on balance neither a plus...