Democratic Sen. Hillary Clinton has $17 million on hand for her re-election campaign in New York, a total driven in part by her potential as a 2008 presidential candidate.

The former first lady collected $6 million from 56,899 donors in the final three months of 2005, bringing her total cash on hand at the end of the year to $17,101,626, according to reports filed Tuesday with the Federal Election Commission.

Clinton is up for re-election this year after first winning the Senate seat in 2000 when she was still first lady. Her fundraising totals and her poll numbers make her the early favorite among potential Democratic candidates for the White House in 2008, though she repeatedly insists she isn't thinking beyond the Senate race.

New York Republicans have struggled to mount a serious challenge to Clinton's 2006 re-election. Recent polls show Clinton more than 25 points ahead of her nearest Republican challenger.

Other Senate incumbents and their challengers nearly matched each other dollar for dollar in fundraising for this year's competitive races, with Republicans fighting to hold their majority against determined Democrats.

The current Senate breakdown is 55 Republicans, 44 Democrats and one Democratic-leaning independent.

In Missouri, where polls show a close race, Democrat Claire McCaskill, the state auditor, raised $915,000 at the end of 2005 for her Senate campaign as she tried to keep pace with incumbent Sen. Jim Talent, R-Mo., whom she wants to unseat.

That was close to the $1.1 million Talent raised in the same three-month period, but McCaskill's overall cash on hand — about $1.26 million — remains well short of the $4.66 million the freshman Republican has in the bank.

Recent polls in Missouri show the candidates in a virtual dead heat less than 10 months before the Nov. 7 election. Neither candidate is expected to face a challenge in party primaries.

One of the most competitive Senate races is in Pennsylvania, where Sen. Rick Santorum, a member of the Republican leadership, trails his Democratic rival, Bob Casey Jr., in several polls. Santorum raised $2.5 million during the final three months of 2005, and he ended the year with $7.8 million in cash. About $100,000 of that came from two December fundraisers that Santorum held with Sen. John McCain, R-Ariz.

Figures for Casey were not immediately available.

In Montana, Republican Sen. Conrad Burns raised $813,956, bringing his total for the period to $4.8 million. He had $3.4 million on hand at year's end.

Democrats have targeted Burns for his relationship with disgraced lobbyist Jack Abramoff, and Burns has already run ads defending himself on the issue. One of the Democrats vying to unseat him, State Auditor John Morrison, has raised more than $1 million. Morrison raised $406,984 during the last quarter.

In the 33 contests this year, Democrats are defending open seats in Maryland and Minnesota. In Vermont, Republican-turned-independent Sen. James Jeffords is retiring. Newly appointed Sen. Robert Menendez, D-N.J., will be looking to win his seat outright after replacing Jon Corzine, who won the state's governorship last year.

Tuesday was the deadline for candidates to report their fundraising totals for a three-month period to the FEC. The numbers were examined closely not only for candidates' viability in 2006, but also the status of the potential 2008 presidential candidates in the Senate.

Republican Sen. George Allen of Virginia raised slightly more than $6.82 million in 2005. He has $6.2 million for his Senate re-election campaign in a race the freshman lawmaker is expected to win easily.

Senators can transfer money from their campaign accounts to use as seed money for a presidential bid.

Sen. Dianne Feinstein, D-Calif., raised $745,000 during the period and said she had $5.7 million cash on hand as of Dec. 31.

California's popular senior senator is seeking a third full term; her fundraising pace has slowed as no formidable challenger has emerged. A conservative former state legislator, Dick Mountjoy, last week announced plans to challenge her, but he raised no money during the reporting period.