President Obama’s decision to exempt young illegal immigrants from deportation may not be the electoral boon it’s cracked up to be.

And in fact, it appears to be turning off more voters than it mobilizes in three key states, according to new polling from Quinnipiac University.

The Quinnipiac polls in Florida, Ohio and Pennsylvania show that, while most voters still like the policy and Obama continues to lead Mitt Romney in all three states, the opposition to the move appears to be significantly more motivated by it — particularly in the two Midwestern states.

In both Ohio and Pennsylvania, more than twice as many respondents say the decision makes them less likely to support the president (27 percent in both) as say it makes them more likely to back him (12 percent in Pennsylvania, 11 percent in Ohio).

In Florida, the split is less pronounced, with 22 percent saying the move makes them less likely to support Obama and 17 percent saying it makes them more likely to support him. Still, though, the opposition wins the day, even in a heavily Latino state (though we should note that Florida’s Latinos — many of them Cuban-Americans — tend to be more conservative than in other states).

What’s most remarkable about the results is that, in all three states, a majority supports Obama’s immigration policy by a significant margin: by 25 points in Florida, 14 points in Ohio and 10 points in Pennsylvania.

So how can a popular policy be a political loser? Put simply, voters who care about the issue most tend to disagree with Obama’s policy.

The numbers harken back to polling conducted after Obama’s decision to publicly support of gay marriage last month. A Gallup poll back then showed that a slim majority of Americans backed the move, but when it came to affecting their vote, 26 percent said it made them less likely to vote for Obama, while just 13 percent said it made them more likely.

As with the gay marriage numbers, many who say the immigration policy makes them less likely to vote for Obama are Republicans who almost certainly weren’t going to vote for him anyway. But the move also appears to be turning off significant swaths of independents.

In Ohio, 26 percent of independents say they are now less likely to support Obama, while just 10 percent say they are more likely to back him. In Pennsylvania, the split is 32 percent less likely and 10 percent more likely. In Florida, the split among independents is 22 percent less likely and 14 percent more likely.

The question from here is how many of these independents were really votes that Obama could win and how many of them are culturally conservative voters that were more likely to back Romney anyway.

The fact that Obama gained ground in both Ohio and Pennsylvania since the last Quinnipiac polls conducted in those states suggests the effect is negligible. Though lots of other factors weigh on the overall head-to-head, of course.

Either way, though, it’s clear that the decision has hardly led independents to rally around the president, and even Democrats aren’t super motivated by it; just one in five Democrats in both Ohio and Pennsylvania say it makes them more likely to support Obama.

One caveat: These are not necessarily the states where the immigration move was supposed to help Obama (with the possible exception of Florida). More likely is that this would help Obama mobilize low-turnout Latino voters in heavily Latino swing states like Colorado and Nevada, along with theoretically helping Obama put Arizona in play (though we are dubious on that count).

By contrast, if there are two key states where the immigration decision could hurt Obama, it would be Ohio and Pennsylvania, with their large swaths of blue collar voters.

The issue strikes against Obama most among this key voting bloc, with which he has struggled in recent years. Over 30 percent of whites without college degrees in Ohio, Pennsylvania and Florida say Obama's immigration policy makes them less likely to support him, while fewer than 10 percent say it makes them more likely to back him. 

Even if the decision does help Obama in some other states, Florida, Ohio and Pennsylvania are much bigger electoral vote prizes than Colorado, Nevada and Arizona. And if the immigration move does, in fact, cost Obama support among some independents who were gettable for him in those states, that could pose a problem.

Scott Clement contributed to this report.