By Greg Giroux, CQ Staff

Here’s another reason the Democrats probably will gain ground in the House of Representatives this year: of the 35 House districts where incumbents are not running this November, 28 are held by Republicans. Given the GOP’s strong defensive crouch, it may not be surprising that Democratic candidates dominate the roster of best-funded candidates for open seats — a key finding of a CQ Politics analysis of recently filed campaign finance reports.

Using campaign cash-on-hand at the end of June as the measuring criterion, seven of the 10 best-funded House candidates in open-seat contests are Democrats. The party’s edge is even more pronounced when you consider that the three Republicans on this list are seeking Republican-held seats, so their victories would not help the Republicans come any closer to overturning the current 236-199 Democratic majority. By contrast, six of the seven Democrats on this list are seeking seats that Republican incumbents are leaving open; Democratic victories in one or more of those six seats would help the party augment its majority.

The 10 best-funded open-seat House candidates are profiled below. Please click here for a chart that includes a longer catalog of candidates. All figures are current to June 30.

U.S. House Candidates in “Open” Districts who reported the most campaign cash-on-hand

1. John Adler, Democrat, New Jersey’s 3rd ($1.5 million). Adler, a state senator, is waging an aggressive takeover campaign for the south-central New Jersey district that 12-term Republican Rep. H. James Saxton is leaving open to retire. Adler was unopposed in the June 3 primary election, while Republican Chris Myers, a local councilman, won a three-candidate GOP primary. That helps explain why Adler has nearly ten times as much to spend as Myers ($155,000). CQ Politics Rating: Leans Republican

2. Linda Stender, Democrat, New Jersey’s 7th ($1.2 million). Stender, a member of the New Jersey Assembly, is running for a north-central New Jersey district she also sought in 2006, when she lost by less than 2 percentage points to Republican Rep. Mike Ferguson , who is not seeking re-election this year. Like Adler, Stender didn’t face opposition in the June 3 Democratic primary, which allowed her to build a large campaign warchest months ahead of the November election. Her Republican opponent is Leonard Lance, a state senator who had $81,000 left in his campaign account on June 30, less than four weeks after he won a crowded Republican primary election. CQ Politics Rating: No Clear Favorite

3. Mary Jo Kilroy, Democrat, Ohio’s 15th ($1.16 million). Kilroy is an elected commissioner in the county that includes Columbus, the Ohio state capital and the population center of a district from which Republican Rep. Deborah Pryce is retiring after eight terms. Kilroy, who nearly defeated Pryce in 2006, was unopposed in the March primary and will face Republican state Sen. Steve Stivers, who ranks eighth on this list. CQ Politics Rating: No Clear Favorite

4. Erik Paulsen, Republican, Minnesota’s 3rd ($1.1 million). Paulsen, a state representative, is vying to succeed retiring nine-term Republican Rep. Jim Ramstad in Minneapolis suburbs such as Bloomington, Brooklyn Park and Plymouth. He’s opposed by Ashwin Madia, a lawyer and military veteran who ranks 10th on this list. Paulsen is unopposed in the Sept. 9 primary, so he’s assured of the Republican nomination. CQ Politics Rating: No Clear Favorite

5. Keith Fimian, Republican, Virginia’s 11th ($1 million). Fimian, the founder of a home inspection business, is vying to succeed retiring seven-term Republican Rep. Thomas M. Davis III in a district that takes most of its population from Fairfax and Prince William Counties near Washington, D.C. This district is among the most difficult for the Republicans to hold, though Fimian — who has loaned his campaign $325,000 — will have the resources to wage a serious campaign against Gerry Connolly, a county executive whose lower cash-on-hand total ($275,000) owes to his big spending ahead of his victory in a four-candidate Democratic primary in June. Fimian was unopposed for the Republican nomination, so he’s spent a much smaller share of his campaign receipts than Connolly. CQ Politics Rating: Leans Democratic

6. Dan Maffei, Democrat, New York’s 25th ($962,000). Maffei, a former congressional aide, is seeking the same Syracuse-based district that he nearly won from veteran Republican Rep. James T. Walsh in the 2006 election. Walsh’s impending retirement is one reason why Maffei merits the early advantage; so is the Democrat’s strong fundraising, especially when compared against that of Dale Sweetland, a former county legislator who began his campaign much later than Maffei and who had $108,000 on hand as July began. The district’s backing of Democratic John Kerry over President Bush in 2004 is another reason why Maffei is more likely than not to deliver this GOP-held district to the Democratic column. CQ Politics Rating: Leans Democratic

7. Debbie Halvorson, Democrat, Illinois’ 11th ($917,000). Halvorson, a state senator, entered the race shortly after Republican Rep. Jerry Weller said that he would not seek re-election in a mildly Republican-leaning district that includes a mix of suburbs, exurbs and rural territory south and west of Chicago. She’s facing a determined Republican challenger in Marty Ozinga, a concrete company executive who has been aggressively raising money ever since he was named by local Republican officials in late April to replace the original Republican nominee, who had withdrawn.

In this year’s second quarter, Halvorson collected as much from political action committees as she did from individual donors. She also received some funds from a pair of joint fundraising committees, Blue Illinois 2008 and Women Lead Victory Fund 2008, that distributed funds to her campaign, as well as to others. CQ Politics Rating: Leans Democratic

8. Steve Stivers, Republican, Ohio’s 15th ($880,000). After initially declining to run for Pryce’s seat, Stivers began his fundraising efforts last November, well after Democratic opponent Kilroy. But Stivers has raised enough to stay competitive with Kilroy, and this race should be highly competitive in part because of the close district outcomes of the Pryce-Kilroy race in 2006 and the Bush-Kerry contest in 2004. CQ Politics Rating: No Clear Favorite