Trenton Garris, right, joins other demonstrators showing their support… (Kevin P. Casey / Associated…)
About one in four Americans say that President Obama's support for same-sex marriage makes it less likely they'll support him this fall, with far more saying it will have no impact on their vote, a new Gallup poll finds.
An additional 13% of the registered voters surveyed Thursday said they were now more likely to support Obama, who announced Wednesday he believed same-sex couples ought to be able to get married.
Republicans were far more likely to say Obama's new position would dissuade them from supporting him. The reaction of independent voters was largely in line with the overall results.
Gallup's Jeffrey M. Jones said in an analysis of the new survey that the partisans' responses would most likely indicate more of a change in the intensity of their vote choice as opposed to an actual change.
The results "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."
A Gallup survey released earlier in the week showed that Americans equally divided on whether to allow same-sex couples to marry -- 50% in favor, 48% opposed.
That marks a shift from just four years ago when only 40% favored allowing same-sex couples to marry, while 56% opposed.
Gallup's daily tracking poll Friday showed Mitt Romney only narrowly ahead of Obama in a hypothetical general election head-to-head, 46% to 45%.