Echoing the recent money-gathering success of the national party committee, Democratic Senate candidates outraised their Republican opponents in seven of the 10 most competitive contests — including six of the eight open seats — during the second quarter of the year, according to financial reports filed with the Federal Election Commission.

Illinois state Sen. Barack Obama (D) continued to wow, raking in better than $4 million from April 1 to June 30, the highest total of any candidate in the top-tier races.

Former White House Chief of Staff Erskine Bowles (D) raised more than $2.6 million for his Senate race in North Carolina, while Colorado state Attorney General Ken Salazar (D) and Rep. Chris John (La.) took in slightly more than $2 million each for their Senate contests.

For Republicans, former Rep. John Thune (S.D.) set the gold standard, raising nearly $3.9 million in the period. He bested Senate Minority Leader Tom Daschle’s $3.1 million total raised in the period, although the Democrat retains a $1.5 million cash-on-hand edge.

These individual numbers come on the heels of the news that for the first time this cycle the Democratic Senatorial Campaign Committee outraised the National Republican Senatorial Committee during a three-month filing period.

The DSCC brought in $15 million to the NRSC’s $11 million from April 1 to June 30. The NRSC still had a cash-on-hand edge with $19 million in the bank to $13 million for the DSCC, however.

DSCC spokeswoman Cara Morris said the July reports “show that Democrats are going to be on an even playing field when it comes to fundraising.”

Dan Allen, Morris’ counterpart at the NRSC, said that a race-by-race analysis shows that Republicans are well-positioned.

He called Morris’ momentum argument “hollow,” noting that “these races are run state by state.”

Perhaps the most surprising element of the July quarterly reports is that in all three Republican-held open seats, the Democratic candidates outraised their GOP opponents.

This margin was most pronounced in Illinois where Obama, who has raised better than $10 million so far this election cycle, is essentially running uncontested at this point.

Following former investment banker Jack Ryan’s (R) decision to leave the race June 25, GOPers have been unable to recruit a replacement candidate into the contest, with former Chicago Bears coach Mike Ditka the latest would-be to say no.

The state’s 19-member Republican state central committee has until late August to name a ballot replacement for Ryan.

Whoever becomes the Republican standard-bearer begins the general election campaign at a distinct disadvantage to Obama, who, after emerging from a crowded March primary, has been transformed into a Democratic superstar. He will deliver the keynote address at the Democratic National Convention in Boston next week.

In Oklahoma, Rep. Brad Carson (D) put together another strong quarter with $1.1 million raised and roughly $2 million on hand.

Carson will face a noncompetitive primary challenge next Tuesday and is expected to avoid a runoff by securing better than 50 percent of the vote.

The Republican picture in Oklahoma is more muddled, as former Oklahoma City Mayor Kirk Humphreys, former Rep. Tom Coburn and state Corporation Commissioner Bob Anthony are all seeking the nomination.

Humphreys led the trio in fundraising from April 1 to June 30 due to a $250,000 personal loan; he has given another $1 million from his own coffers since the filing deadline.

Coburn, thanks in part to the endorsement of the Washington-based Club for Growth, brought in $722,000 in the period but had just $365,000 left on hand.

Anthony lagged far behind his two GOP opponents with $267,000 raised for the period.

In Colorado, Salazar bounced back from a shocking defeat at the state party convention in June to crest the $2 million mark and re-establish the state as one of Democrats’ best takeover opportunities nationwide.

Salazar is the heavy favorite against educator Mike Miles in the state’s Aug. 10 primary despite Miles’ convention victory, which gave him top billing on the ballot.

On the Republican side, brewing magnate Pete Coors outraised former Rep. Bob Schaffer at nearly a 4-to-1 clip from April 1 to June 30 and had $600,000 more on hand at the end of the reporting period.

Schaffer’s lowly financial standing is already getting a boost, however, from both the Club for Growth and the Colorado Conservative Voters, a “527” organization led by former Sen. Bill Armstrong (R) — one of Schaffer’s most ardent backers.

In the five Democratic-held open seats considered to be at the center of the fight for control of the Senate, the news is more mixed.

In North Carolina and Louisiana, Bowles and John outraised their Republican opponents in the period but trailed in cash on hand.

Bowles posted his second consecutive $2 million quarter, again besting Rep. Richard Burr (R).

But Burr has been in the race for 18 months, in the process accumulating a huge cash-on-hand total of $6.6 million. Bowles had $3.7 million in the bank at the end of June.

Similarly in Louisiana, John posted a huge fundraising quarter, bolstered by the transfer of $1 million from his House account. But he still lags $900,000 behind Rep. David Vitter (R) in funds left to spend on the race.

John’s task is also complicated by the presence of state Treasurer John Kennedy (D) in the contest given that all candidates, regardless of party affiliation, will appear together on the Nov. 2 ballot. Kennedy ended June with $1 million on hand.

Thanks to a $975,000 personal donation, wealthy businessman Cliff Oxford (D) outraised all three potential Republicans in the Peach State Senate race, but his spending is not likely to increase Democrats’ chances to hold Sen. Zell Miller’s (D) seat.

Oxford is using his cash infusion on a flight of television ads in the runup to Tuesday’s primary, in which he will face off against Rep. Denise Majette.

Rep. Johnny Isakson is the clear leader on the Republican side and hopes to avoid a runoff Tuesday by surpassing 50 percent of the vote.

Republicans scored clear fundraising victories in Florida and South Carolina during the second quarter, the latter due to a contested primary and runoff victory in June by Rep. Jim DeMint (R).

Despite DeMint’s $1.9 million raised, he had only $98,000 on hand at the end of June, a total dwarfed by state Superintendent of Education Inez Tenenbaum’s $2 million war chest.

DeMint should have little trouble closing the gap, however, having already benefited from two fundraising events with Sen. Lindsey Graham (R-S.C.) since the June 22 runoff. Vice President Cheney will travel to the state to raise money for DeMint this week.

The two incumbents most heavily targeted by the national parties were both outraised in their July reports.

After formally entering the race in January, Thune has raised more than $6 million — the total amount he spent in his 2002 race against Sen. Tim Johnson (D).

Daschle has already raised $13.5 million and spent more than $9 million on the contest — including $2.5 million in the past three months.

Thune has disbursed $2.2 million in the contest to date.

In Alaska, former Gov. Tony Knowles (D) brought in nearly $50,000 more than Sen. Lisa Murkowski (R) and halved the incumbent’s cash-on-hand lead.