Hillary Clinton is far ahead of the pack in fundraising for 2006–and thus, 2008–despite being essentially unopposed.

Clinton, who faces two little-known Republican opponents in her bid for a second term in November, raised $6 million from Jan. 1 to March 31 — outdistancing the 32 other senators seeking reelection this fall as well as her prospective rivals for the presidential nomination. Clinton has now raised better than $39 million for her reelection effort since coming to the Senate in 2001 and ended last month with nearly $20 million in the bank. Election law allows anything left over from her Senate campaign to be transferred to a presidential campaign.

Not that she’ll have any trouble raising money for that, anyway. Still, while raising a lot of money does not guarantee victory (Remember Phil Gramm’s 2000 run?) it is a significant indicator of support that so many people are placing their bets on her candidacy.

Of note, too, is this:

Among Republicans, Sen. George Allen (Va.) is showing the most fundraising muscle, collecting $1.75 million for his reelection fight and closing the quarter with $7.2 million on hand. Unlike Clinton, however, Allen faces a potentially serious challenge this fall from either former technology lobbyist Harris Miller (D) or Reagan administration Navy secretary James Webb (D), and he is likely to spend much of his war chest to defend his seat.

Allen is widely considered a dark horse for the Republican nomination in 2008. Aside from the Rick Santorum seat, this may be the most targetted race in the country in November. I think Allen wins it, easily over Miller and narrowly against Webb. If he doesn’t, however, I don’t see how he can be a plausible presidential candidate.