Sen. Charles Schumer (D-N.Y.) will head the Democratic Senatorial Campaign Committee in the 2006 cycle, bringing his massive fundraising operation and aggressive political instincts to a party devastated by a four-seat loss in the 2004 elections.

Schumer accepted the post Monday after spending the weekend deliberating whether to abandon his gubernatorial hopes. His decision to take the DSCC job effectively rules out a run for governor in 2006, when three-term incumbent George Pataki (R) is expected to step down.

Incoming Senate Minority Leader Harry Reid (D-Nev.) offered the position to Schumer late last week, dangling both a chance to be the “point person” in crafting the Democratic message and a spot on the coveted Finance Committee if he accepted.

“To me, this was a dream offer,” Schumer said in a statement, referring to the chance to serve on Finance while keeping his current assignments on Judiciary and Banking. “This was an offer that for the sake of New York I could not refuse.”

At the DSCC, Schumer succeeds New Jersey Sen. Jon Corzine as chairman. He will also apparently vault over Sens. Hillary Rodham Clinton (N.Y.) and Byron Dorgan (N.D.) in the development of a cohesive message strategy for Senate Democrats.

Senate Republicans, for their part, will elect a successor to National Republican Senatorial Committee Chairman George Allen (R-Va.) on Wednesday.

In that race, the two contenders are North Carolina Sen. Elizabeth Dole and Minnesota Sen. Norm Coleman, neither of whom is thought to have a decided edge.

Schumer’s decision to walk away from the governor’s race leaves many Washington Democrats breathing a sigh of relief, since he was seen as the only member of the Caucus willing and able to do the job.

Reid said in a statement that he was “grateful to Senator Schumer for taking on this challenge,” adding that he was “confident he will succeed.”

Schumer takes the reins of the DSCC at a moment of low Democratic morale, as the reality of the party’s four-seat loss sinks in.

In 2006, there will be 17 Democratic Senators up for re-election, a total that includes eight freshmen and six Senators who will be older than 70 on Election Day.

Republicans must defend 15 seats. Of those, only one — the Tennessee seat being given up by Senate Majority Leader Bill Frist — is currently open.

The most potent weapon in Schumer’s arsenal clearly is his talent for fundraising.

Since winning election to the Senate in 1998, Schumer has emerged as one of the chamber’s strongest fundraisers — perhaps eclipsed only by Sen. Clinton.

In preparation for his 2004 re-election, Schumer raked in upwards of $26 million. Of that total, he spent only a pittance against state Assemblyman Howard Mills (R), whom he beat with 71 percent of the vote.

Schumer’s gargantuan fundraising totals led to widespread speculation that he was eyeing the governor’s race in 2006 and that he hoped to transfer the bulk of his Senate war chest into a state account.

Although such a transfer would be legal under New York State law, the Federal Election Commission banned the procedure following the passage of the Bipartisan Campaign Reform Act in 2002.

After repeated pleas from party leadership, Schumer donated roughly $2.5 million from his Senate campaign committee to the DSCC, making him the largest single donor to the organization in the Democratic Caucus.

Somewhat shockingly, the DSCC outraised the NRSC during the 2004 cycle, a feat considered unimaginable after BCRA banned the raising and spending of soft money by the national parties.

Those close to Schumer point out that while his fundraising prowess may be his prime selling point, he is also a savvy strategist.

“Chuck is one of the hardest working, smartest, most astute people in government in the country,” said Josh Isay, a New York City-based media consultant who managed Schumer’s 1998 Senate campaign.

In that race, Schumer was not expected to emerge from a Democratic primary field that included such well-known commodities as Geraldine Ferraro, the former vice presidential candidate, and Mark Green, a 1986 Senate candidate who at the time was New York City public advocate.

But thanks to an infusion of more than $5 million he had stockpiled in his House account, Schumer won the primary convincingly with 51 percent. He then went on to unseat two-term Sen. Alfonse D’Amato (R) in the fall. (D’Amato himself served as NRSC chairman during the 1996 cycle.)

Observers point to Schumer’s hard-driving personality and willingness to court the media as a big reason for his political success.

“He is a great communicator with fantastic political instincts, and no one will work harder,” said Democratic consultant Howard Wolfson, a New York native.

Even Schumer’s most loyal allies acknowledge that the Senator has gained a reputation of being tough on his staff. But they quickly add that he is much tougher on himself.

“I worked for Chuck for six years,” said Isay. “He pushes his staff hard, but he works harder than all of his staff.”

Mike Lynch, Schumer’s current chief of staff, is the leading candidate to take over as executive director at the DSCC, party sources said.

Andy Grossman, who held that same post for a portion of the 2004 cycle, praised Schumer as a “really serious man who gets the most out of his staff.”