Former Rep. Pat Toomey (R-Pa.) has opened up a nine-point lead on Rep. Joe Sestak (D) in Pennsylvania's Senate race and holds a commanding edge with independents.

New numbers from Public Policy Polling show Toomey ahead of Sestak 45 percent to 36 percent. Among independent voters, Toomey leads 50-23.

Pollster Tom Jensen points to President Obama's sinking popularity in the state as one of the primary reasons for Toomey's lead. The president's approval in Pennsylvania now stands at just 40 percent, while 55 percent of likely voters disapprove. 

There are also more disaffected '08 Obama backers in Pennsylvania than there are nationally, according to PPP.

"Our national poll last week found only 7% of Obama voters are now unhappy with the job he's doing but in Pennsylvania the figure is 15%," writes Jensen. "Toomey has a 14 point lead with those disaffected Obama voters, showing the extent to which those voters moving away from Obama are moving away from the Democratic Party in general."

One issue that could move independents is the growing controversy over plans for an Islamic cultural center and mosque near New York's Ground Zero.

New York City Mayor Michael Bloomberg, one of the project's biggest backers, endorsed Sestak in Philadelphia Tuesday, while Toomey led the morning by denouncing plans for the mosque. 

A spokesman for the Toomey campaign called the project "provocative in the extreme." 

Sestak, meanwhile, is trying to straddle the fence on the mosque question. A spokesman said Monday that the congressman "believes there is a constitutional right to religious freedom and separation of church and state that applies equally to all Americans." 

But spokesman Jonathon Dworkin said Sestak "is not looking to say what’s best for New York as long as that right is respected — he is focused on Pennsylvania."