Despite the competition of a presidential primary, Senate Democrats continue to raise money at a formidable pace, bringing in $8.2 million in March alone and maintaining their 2-1 cash advantage over the GOP.

According to the most recent Federal Election Commission filings, the Democratic Senatorial Campaign Committee collected $16.9 million for the first quarter of the year and has amassed $72.3 million overall this cycle. The DSCC has finally retired a long-standing debt and now has $37.8 million in the bank. The National Republican Senatorial Committee has less than half that amount — about $17.3 million in cash on hand.

“We’ve done real well,” DSCC Chairman Charles Schumer (N.Y.) said Friday. “People around the country really want change.”

The NRSC collected $4.2 million in March, bringing its overall fundraising this cycle to $43.5 million and total three-month tally to $11.7 million. That amount, while significantly less than the DSCC’s quarterly haul, represents a solid fundraising period for the Republican fundraising arm, which has struggled this cycle to overcome serious political handicaps.

Republicans are defending 23 Senate seats in 2008, compared with the Democrats’ dozen. What’s more, the GOP is facing serious challenges to at least five incumbents, while the Democrats are eyeing just one vulnerable Senator — Mary Landrieu (La.).

Democrats have a narrow 51-49 majority hold on the Senate and are aiming to inch closer to a critical threshold of 60 seats, which would give them enough votes to overcome minority-led filibusters.

Sen. John Ensign (Nev.), chairman of the NRSC, kicked off the two-year cycle by setting an ambitious goal of matching Schumer’s DSCC haul in 2006 of $113 million. But earlier this year, Ensign acknowledged that target was out of reach, especially if the committee hoped to keep enough cash on hand to help defend its imperiled incumbent GOP Senators. The more ambitious figure could be reached only by spending heavily on fundraising, which would dry up available cash on hand.

Even with that original goal now elusive, Rebecca Fisher, spokeswoman for the NRSC, said Friday that contributors are beginning to recognize the significance of the 2008 elections, saying: “We continue to see a positive response from donors that are realizing just what a Democrat majority really means to them.”

The NRSC continues to operate with no debt, which had been an issue for the Democrats, who started out the 2008 cycle $6 million in the red. The DSCC had been paying down that debt by $500,000 each month during the past 12 months, finally retiring it last month.

Schumer said Democrats are on pace to match their fundraising success of the previous election period, which led to a six-seat gain and a new majority for the party. The New York Democrat said he remains baffled that the DSCC has continued its success given it has had to compete with the fundraising of two presidential candidates, who have broken fundraising records this election year.

In March, Sen. Barack Obama (Ill.) took in about $40 million in contributions, while Sen. Hillary Rodham Clinton (N.Y.) raised about $20 million.

“We’re on track,” to surpass last year’s DSCC fundraising total, Schumer said. “If you compare it to the first five quarters [of last cycle], this time we are considerably ahead. It’s an interesting thing. We were worried the presidential race would be a drag on that. I can’t figure it out. It’s actually better for us.”