The Obama campaign is pouncing on this new poll finding that a majority of Americans wants Mitt Romney to release his tax returns:

A majority of Americans, including almost a third of Republicans, say GOP presidential contender Mitt Romney should release more tax returns than the two years he has promised to disclose, a USA TODAY/Gallup Poll finds.

Americans want Romney to release his returns by a 17 point margin, 54-37. And 53 percent of independents say he should release them.

What’s particularly interesting is that the same poll also finds that a plurality doesn’t think that the tax returns of candidates are relevant in general, which in theory should help Romney’s argument:

Forty-seven percent call it “largely irrelevant” to helping voters decide who should be president while 44% say it provides “legitimate information that helps voters make better decisions.”

But in Romney’s case, Americans want them released, and in his particular case, a plurality thinks what is hidden in the returns would be damaging to him:

While 42% predict the release of additional returns would not reveal anything politically harmful, 44% believe it would include damaging information — including 15% who say they believe the revelations would be so serious that they would “show he is unfit to be president.”

What this suggests is that even if many voters are generally inclined against thinking such information is relevant, Obama and Dems may have succeeded in raising enough doubts about Romney that a majority want to see what’s in his returns and a plurality even suspects there’s something he doesn’t want voters to see. Which of course will only encourage Dems to continue pressuring him to release them, and could also encourage more Republicans to tell him he’s got to do the same and get this behind him.