The national campaign committees have spent $18 million combined on a few House races in Pennsylvania, a state Democrats see as critical to their hopes of capturing control of the House.
The spending is more than the $12 million combined spent in Ohio or the $9 million combined dedicated to Connecticut, the other top states with several competitive House races.
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The independent expenditure money primarily pays for television ads and can make the difference in competitive races — particularly if a candidate is short on cash. Democrats must gain 15 seats in next week's election to win control of the House.
In Pennsylvania, the money has gone to help candidates in five contested House races, with most of it concentrated in three congressional districts in the Philadelphia suburbs, according to reports filed with the Federal Election Commission.
Democratic Party registration has increased in recent years in the traditionally Republican region around Philadelphia. All three districts went for Al Gore in 2000 and John Kerry in 2004.
The Philadelphia television market is among the top five most expensive in the nation.
"We get involved in races where we believe we can make a difference," said Ed Patru, a spokesman for the National Republican Congressional Committee. He added that $1 million doesn't go as far for TV ads in Philadelphia as it does in rural Indiana, where there are also competitive races.
The NRCC has focused on ads accusing Democrats of wanting to raise taxes. The Democratic Congressional Campaign Committee's spots have stressed GOP incumbents' ties to President Bush.
About $6 million combined has been spent on the rematch between Rep. Jim Gerlach, a two-term Republican, and attorney Lois Murphy, who nearly beat him in 2004. The committees have spent an estimated $3 million on each candidate.
The NRCC has spent nearly $3 million to support Rep. Mike Fitzpatrick, a freshman, while the DCCC spent close to $2 million for his opponent, Iraq war veteran Patrick Murphy.
About $3 million from the NRCC has gone to help Rep. Curt Weldon, a 10-term lawmaker who is under investigation by the FBI, while the DCCC has spent about $2 million to support his opponent, Joe Sestak, a former Navy vice admiral.
In rural northeast Pennsylvania where advertising is less expensive, the NRCC has spent more than $1 million to help Rep. Don Sherwood, who had a seemingly safe seat until he admitted last year to an extramarital affair. Democrats have spent a little less to help Democrat Chris Carney.
Outside Pittsburgh, the NRCC has spent at least $300,000 to support Rep. Melissa Hart, while the DCCC has spent about half that to support challenger Jason Altmire.
"This is a top battleground for Democrats in the country and Republicans are on the ropes and forced to defend some of the most vulnerable incumbents in the country," said Jen Psaki, a DCCC spokeswoman.