Chalk up the first round of the 2010 fundraising wars to Senate Democrats.

As first-quarter Federal Election Commission reports trickled in last week and the number of Democratic candidates or incumbents up for re-election who raised $1 million or more climbed into the double digits, party operatives could hardly hide their excitement.

“If you look at the success of our candidates, it shows that not only are they in great positions to run competitive races, but it shows how excited people are to support Democrats who will partner with President Barack Obama in getting this economy back on track,— Democratic Senatorial Campaign Committee spokesman Eric Schultz said last week.

In the end, 11 Democrats with their eyes on Senate seats next year topped the $1 million mark during the Jan. 1 to March 31 fundraising period. On the other side of the aisle, just three Republicans — Sens. John McCain (Ariz.) and Arlen Specter (Pa.) and former Rep. Rob Portman, who is running for Senate in Ohio — could claim the same level of fundraising success. (Kansas Republican Rep. Todd Tiahrt showed nearly $1.4 million raised for the quarter, but that includes more than $1 million transferred from his former House account.)

But it’s still very early in the 2010 cycle, and Senate Republicans attributed at least part of Democrats’ early fundraising advantage to the simple fact that they now control both ends of Pennsylvania Avenue.

“Obviously, being in the majority the Democrats have the ability to raise more K Street money,— National Republican Senatorial Committee spokesman Brian Walsh said on Friday.

And that kind of fundraising can have some drawbacks, Walsh said, if it reinforces an image that a candidate is a Washington, D.C., insider. He pointed to vulnerable Sen. Chris Dodd (D-Conn.) as an example.

Dodd raised more than $1 million in the first quarter of the year, but his FEC report showed that less than $5,000 came from donors in Connecticut. “He may have raised a lot of money in Washington, but clearly none of that came from constituents in Connecticut,— Walsh said. “I think that exposes some of their candidates to potential liabilities down the road.—

GOP operatives can also claim some bragging rights over Portman hauling in the most cash of any single Senate candidate during the first quarter.

Portman is facing a GOP primary challenge from Cleveland auto dealer Tom Ganley, and state Auditor Mary Taylor (R) could also run. But with $3.1 million raised in the first quarter and more than $3 million of that in the bank, Portman looks very solid early on. But that figure includes more than $1.4 million Portman transferred from his old House campaign account to his Senate committee.

On the Democratic side in the open-seat Buckeye State race, Lt. Gov. Lee Fisher turned some heads by raising a little more than $1 million during the first quarter.

Top Democratic first-quarter fundraising honors went to appointed Sen. Kirsten Gillibrand, who pulled in a monster $2.3 million by the end of March and ended the quarter with $2.2 million in the bank. She didn’t transfer any money from her old House account.

The moderate Gillibrand will certainly need the money, particularly if she picks up a strong liberal primary challenger. At least five Democratic House Members are mentioned as possible New York challengers, and last week, Manhattan Borough President Scott Stringer (D) set up an exploratory committee for a possible Senate bid. If Gillibrand is successful in winning the Democratic nomination, she could face well-funded Rep. Peter King (R) in the general election. King ended March with $1.1 million in cash on hand.

Second among Democratic fundraisers was Senate Majority Leader Harry Reid (Nev.), who took in more than $2.2 million and banked more than $5 million. Although Republicans consider Reid vulnerable, they have no obvious challenger. And one potential GOP contender, ex-Rep. Jon Porter, had just $8,000 left over in his old House campaign account.

In Pennsylvania, Specter raised another $1.3 million to add to a war chest of more than $6.7 million by the end of March. Specter is facing a primary challenge from former Rep. Pat Toomey (R), who until recently was president of the powerful anti-tax group the Club for Growth. Toomey, who has already been endorsed by the club after getting into the race earlier this month, is sure to be well-funded, but a few potential Democratic challengers also boasted large campaign bank accounts at the end of March.

Democratic Reps. Allyson Schwartz, Joe Sestak and Patrick Murphy have all been mentioned for the Senate contest. Sestak, who had a $3.3 million war chest as of March 31, said in a statement last week that he’s focused on his job in the House and “beyond that, I have made no decision about my future.—

A spokeswoman for Schwartz, who had $2.1 million in the bank at the end of the quarter, said Friday the Congresswoman “has not ruled out— a Senate bid in 2010.

With just $252,000 in the bank, Murphy had less cash on hand than the $584,000 reported by the leading Democrat in the race so far, Joe Torsella. Torsella, who is close to Pennsylvania Gov. Ed Rendell (D), is the former head of the National Constitution Center.

The Senate’s most vulnerable Republican incumbent, Sen. Jim Bunning (Ky.) didn’t help his cause by raising just $262,980 and reporting $375,747 in the bank at the end of March. Bunning, who critics in his own party have described as a political dead man walking, has blamed his poor fundraising totals on GOP leaders — including his fellow Kentuckian and Senate Minority Leader Mitch McConnell (R) — who he says are trying to force him to quit the race by discouraging donors to give to his campaign.

Bunning had less cash on hand than the $389,000 that Lt. Gov. Dan Mongiardo (D), who entered the race in January, reported having in his coffers. Mongiardo raised $430,000 since throwing his hat into the race. Kentucky Attorney General Jack Conway (D) also announced plans to run earlier this month, but his first fundraising report will come at the end of the second quarter, in June.

But Bunning wasn’t the lowest fundraising incumbent of the first quarter. That dubious distinction belongs to appointed Sen. Roland Burris (D-Ill.), who checked in with just $845 raised, which gave him exactly $845 in the bank and little else to build a re-election campaign on.

Jude Marfil, Liisa Rajala and Charlotte Wester contributed to this report.