By John Ostapkovich

PHILADELPHIA (CBS) — Now that the presidential battle lines are drawn, the question of who will win the favor of independents in the fall election could be the critical one.

Jacqueline Salit says that’s the $64,000 question — or maybe more, given all the money in politics.

As president of IndependentVoting.org and author of Independents Rising, she’s both been involved in and studied a phenomenon that now includes about 40 percent of American voters.

She says they elected Barack Obama in hopes of post-partisanship, then turned on him in 2010 as Congress remained locked in trench warfare.

“Independents reacted strongly to that, switched horses and gave their support to GOP Congressional candidates in the 2010 mid-terms, not because they’d become Republicans but because they don’t like partisan politics,” she tells KYW Newsradio.  “That’s their message, so they’re hugely influential but largely unorganized.”

But Salit can’t predict which way they’ll go this year.

“I think independents are looking to see whether the president or his opponent are going to give voice to this central issue in American politics today, which is overcoming political partisanship,” she says.

Judging from the tone of current political ads, however, independents may have a long wait.