With 39 days left until the midterm elections, the National Republican Congressional Committee has increased its total financial commitment in Democratic-held districts. The NRCC has now committed a total of $35 million to advertising in 55 districts for the fall campaign. House Republicans are now spending, or planning to spend, in well more than the 39 seats needed to win the majority. The committee's initial ad reservation was $22 million in 41 districts. According to a GOP source with knowledge of the committee's thinking, this is just the beginning of an aggressive strategy to capitalize on the favorable political climate. "There is plenty more coming," the source said. Of the 55 districts the NRCC is spending in, just one is held by a Republican: Illinois' 10th district, which Rep. Mark Kirk is vacating to run for Senate. The latest targets, Roll Call confirmed with the source, include two open seats in Massachusetts and Washington, as well as four Democratic incumbents: Reps. Ike Skelton (Mo.), Martin Heinrich (N.M.), Christopher Carney (Pa.) and Steve Kagen (Wis.). In Washington, Rep. Brian Baird's retirement opened the door for one of the top open-seat battles between Republican Jaime Herrera and Democrat Denny Heck. It's one of a couple Democratic districts in play in the state. Massachusetts' 10th district is one of the latest additions to the competitive map this cycle, as Rep. Bill Delahunt (D-Mass.) is retiring after never having a close re-election race. Other recent additions to the NRCC's target list have included districts in Virginia and North Carolina and two in Arizona. The NRCC has reserved airtime in three districts each in Florida, Illinois, Ohio and Virginia, as well as five districts in Pennsylvania. The Democratic Congressional Campaign Committee reserved $48 million in TV time in 60 districts, all but six of which are districts it is defending. It has been shifting its reservations in several states since the initial reservations, but the committee did not respond to a request for an update on its commitment.