More say it makes them less likely rather than more likely to vote for Obama

PRINCETON, NJ -- A majority of Americans, 60%, say President Barack Obama's newly announced support for same-sex marriage will make no difference to their vote. Twice as many say it will make them less likely to vote for Obama as say more likely, though roughly half of the "less likely" group are Republicans who probably would not support Obama anyway.

The results are based on a May 10 USA Today/Gallup poll conducted in response to Obama's May 9 announcement that he supports legalizing gay marriage. Obama is the first president to publicly support gay marriage while in office. The poll finds 51% of Americans approving of his position, essentially matching the 50% of Americans who support gay marriage in general, and similar to his 49% overall job approval rating.

The six in 10 Americans who say Obama's position on same-sex marriage will not affect their vote could be an underestimate because Republicans disproportionately make up the group who say they are less likely to vote for Obama, and Democrats disproportionately make up the group who say they are more likely to vote for him. It is probably safe to assume, given the strong relationship between party identification and vote choice, that most of those voters would have voted for or against Obama regardless of his view on gay marriage.

Partisans' responses to the question may therefore indicate more of a change in the intensity of their vote choice as opposed to an actual change in the candidate they support.

Thus, a key to assessing how the change in Obama's view of same-sex marriage will affect his vote share this fall would be to look at its effect on independents, and on Democrats and Republicans whose views are different from the majority of their party.

Specifically, 23% of independents and 10% of Democrats say it makes them less likely to vote for Obama, while a smaller 11% of independents and 2% of Republicans say it makes them more likely to vote for Obama. Those figures suggest Obama's gay marriage position is likely to cost him more independent and Democratic votes than he would gain in independent and Republican votes, clearly indicating that his new position is more of a net minus than a net plus for him. However, those figures also underscore that it is a relatively limited group of voters -- about one in three independents and fewer than one in 10 Republicans or Democrats -- whose votes may change as a result of Obama's new stance on gay marriage.

It is important to note that the poll's results give a sense of Americans' immediate reactions to Obama's position. It is possible that the impact of Obama's same-sex marriage position will ultimately be greater or lesser, depending on the attention paid to the same-sex marriage issue during the duration of the presidential campaign.