Officials at the Democratic Senatorial Campaign Committee have purchased or reserved an estimated $4.4 million of television air time for commercials to boost Rep. Joe Sestak, the party's


candidate for Senate, according to sources who track media buys.

    The committee has spent $546,075 to run broadcast and cable ads in all the state’s six major media markets beginning today through Aug. 26. That’s on top of what DSCC has spent over the past week: $493,879 on  a TV spot attacking Republican Pat Toomey for the part of his career spent on Wall Street, and for being an advocate for the financial-industry when he was in the U.S. House.

    Just to be safe, DSCC also reserved three weeks’ worth of time in October, when the airwaves get crowded close to election time.

    The national party’s involvement comes as two independent polls out this found Toomey pulling to a wider lead in head-to-head matchups than previous surveys showed. Rasmussen Reports had Toomey up 46 percent to 37 percent, while Democratic-oriented Public Policy Polling had it at 45-36 percent, in Toomey’s favor. Both polls identified Obama’s falling approval rating in Pennsylvania and found the Republican doing better among independents.

    And, until the Democrats’ Senate campaign arm got involved, Toomey had been running unanswered ads depicting Sestak as a liberal for several weeks. Toomey, who did not have a competitive primary, has more money, and Sestak has shown he likes to hold his fire until the final weeks of a campaign.

   Democrats put out some results from their own poll on the race, done by the Garin-Hart-Yang Research Group. Toomey had a narrower lead, 46 percent to 44 percent in the survey of 800 likely voters conducted from Aug. 12-15.

   Wherever the Senate race stands, Democrats want to make sure they don’t get caught short in the define-your-opponent-early department.