Rep. Joe Sestak, the Democratic Senate hopeful in Pennsylvania, is in trouble on a number of fronts, according to a poll released by Quinnipiac University on Wednesday morning.

Former Rep. Pat Toomey (R) led Sestak 50 percent to 43 percent in the survey of 684 likely Pennsylvania voters taken Sept. 15-19. The margin of error was 3.8 points.

Beyond the head-to-head matchup, however, a number of factors suggest that Sestak is facing an uphill battle.

The first is the popularity of President Barack Obama. Likely voters disapprove of the job the president is doing, 56 percent to 40 percent. They say they want a Senator who opposes, rather than supports, the president’s policies, by 52 percent to 43 percent.

Further, by 46 percent to 35 percent, likely voters reported that they want Republicans to control the Senate after the November ballots are counted.

“Pat Toomey is in a good place, ahead by 7 points with six weeks to go. But Congressman Joe Sestak has proven himself a tough competitor so it’s too early to order the champagne,” Peter Brown, assistant director of the Quinnipiac University Polling Institute, said in a statement.

He continued: “Toomey’s lead among independents is why he is ahead. With only 7 percent of the likely voters undecided and another 14 percent who are for a candidate saying they might change their mind, the battle for the Senate seat appears likely to come down to a relatively small number of voters and in the final weeks expect the campaigns to target their messages for those undecided and softly committed voters.”

The National Republican Senatorial Committee pounced on the results, which come despite the Democratic Senatorial Campaign Committee having spent $2.5 million on three separate television advertisements since mid-August.

“With only 41 days until the general election, this latest poll demonstrates once again that Pennsylvanians are tired of the status quo and have rejected liberal Congressman Joe Sestak’s out-of-control spending agenda in Washington, which is why they are enthusiastic about electing Pat Toomey as their next U.S. Senator this November,” NRSC spokeswoman Amber Marchand said.

Though the NRSC has yet to begin running ads through its independent expenditure arm in Pennsylvania, Toomey is getting some help from the U.S. Chamber of Commerce and the Club for Growth, which have already spent $203,000 and $464,000, respectively, on independent media buys in the race.

The DSCC cited an Aug. 20 internal poll that showed Toomey up by just 2 points.

“Pat Toomey spent years rubber-stamping disastrous Bush economic policies and standing with Wall Street and the special interests rather than Pennsylvania families,” DSCC spokeswoman Deirdre Murphy said. “And that’s why he’s going to have a tough time come November.”