Pennsylvania voters gave Sen. Bob Casey “OK marks” heading into the 2012 election, according to a Quinnipiac poll released Thursday that suggests the freshman Democrat could be vulnerable.

Just 39 percent of voters polled between Dec. 6 and 13 approved of Casey’s job performance; 29 percent disapproved and 32 percent didn’t know or didn’t answer. His approval rating is down significantly from a high of 56 percent in May 2009.
 
“Although there is a sense in the political community that Casey will be a strong bet for re-election, his numbers are not overwhelming,” said Peter Brown, assistant director of the Quinnipiac University Polling Institute.
 
Indeed, many Keystone State Democrats and Republicans think Casey is a strong bet for re-election largely because of the GOP’s weak prospects. A challenger has yet to emerge, and despite major Republican gains in the midterms, the evolving list of potential candidates isn’t particularly frightening for the Casey campaign.
 
Perhaps that’s why Quinnipiac didn’t test head-to-head matchups, as other pollsters sometimes do in similar situations. Instead, Quinnipiac simply asked voters if they would support Casey “or the Republican candidate” in 2012.
 
Casey led the generic Republican 43 percent to 35 percent with another 11 percent saying it depended on the candidate and 11 percent more saying they did not know. Roll Call Politics rates this race as Leans Democratic.
 
Not surprisingly, the state Democratic Party said the numbers show the incumbent Democrat “is popular and in a strong position for re-election.”
 
“They support him over a Republican by a wide margin — even in a difficult political environment,” said Mark Nicastre, state party spokesman. “While Republicans struggle to find a serious candidate to challenge Sen. Casey, he has remained focused on creating jobs and cutting taxes for the middle class. This poll shows that Sen. Casey’s work is appreciated by the voters, and it will undoubtedly keep a few more Republicans on the sidelines.”

There’s another thing that may keep more Republicans on the sidelines.
 
At least two of the stronger politicians rumored to have interest — Reps. Charlie Dent and Jim Gerlach — were recently awarded coveted committee assignments for when the GOP assumes the House majority next session. Gerlach will serve on Ways and Means and Dent will sit on Appropriations — powerful assignments that they may be reluctant to abandon.
 
Dent’s office sent out a statement last week noting that he is one of only seven Republicans being added to the committee, which will shrink from 60 to 50 Members next year. He is also the first Republican from Pennsylvania to serve on the Committee since the 110th Congress.

“This appointment will bolster the voice of Pennsylvanians, especially those living in the 15th District, in critical discussions involving federal spending,” Dent said in a statement.
 
Gerlach, whose brief gubernatorial run last cycle revealed his ambition for statewide office, was also thrilled with his assignment: “I am honored to have this tremendous opportunity to boldly confront the huge economic challenges facing our country by reining in wasteful Washington spending and empowering families to keep more of their hard-earned pay,” Gerlach said.

Aside from Dent and Gerlach, the short list of potential challengers includes Republican state Sens. Jake Corman and Kim Ward and wealthy conservative talk radio host Glen Meakem.
 
None are thought to be particularly dangerous to Casey. But the Democrat’s ultimate success may be tied closely to the top of the ticket.
 
President Barack Obama’s popularity isn’t exactly thriving in the Keystone State, where Democrats hold a substantial voter registration advantage. Just 41 percent of voters told Quinnipiac they would vote for Obama if the election were held today, compared with 37 percent who would back a generic Republican. Only 44 percent said that the president deserves to be re-elected.

Obama won Pennsylvania in 2008, and the state backed Sen. John Kerry in 2004. 

Of course, a lot can change in two years, Brown said. And the president’s numbers have actually improved in recent months.
 
“Depending on how popular the president is in Pennsylvania in 2012, and how Sen. Casey conducts himself during the next 23 months, that could be a plus or a minus for Casey’s re-election prospects,” he said.

Quinnipiac surveyed 1,584 Pennsylvania voters between Dec. 6 and 13. The survey’s margin of error is 2.5 points.