Hillary Clinton's poll numbers have been eroding in three of the key early nomination contests, which could render her national lead meaningless, writes Howard Fineman for MSNBC:

Sen. Hillary Clinton's campaign is teetering on the brink, no matter what the meaningless national horserace numbers say. The notion that she has a post-Iowa "firewall" in New Hampshire is a fantasy, and she is in danger of losing all four early contests, including Nevada and South Carolina - probably to Sen. Barack Obama, who is now, in momentum terms, the Democratic frontrunner.

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If she is going to argue that Obama is unelectable in the fall - if she is going to argue that the Democrats cannot afford to take the risk on a Southside Chicago street organizer - she had better get to it in the debate this week. But it is a tricky proposition. In a way, Hillary is trapped by her own do-it-yourself feminist ethos. She should have surrogates out there pounding away at Obama. I haven't seen them. And her husband, evidently, won't do it. Why should Bill Clinton tarnish his image as "America's first black president" by attacking the man who might be the real deal? His circle is beginning to complain, loudly, about how Hillary is running her campaign. That kind of circular firing squad chatter is the first sign of a campaign headed into oblivion.

Read the whole article at the link above (Fineman also evaluates the other leading contenders in both parties). Up until her shaky performance at the Philadelphia debate at the end of October, Hillary's campaign had been on cruise control with formidable leads in all the early states except Iowa (and in strong contention there), as well as nationally. From that point on, it's been one mistake, followed by a gaffe, followed by another unforced error.

The previous "conventional wisdom" had been that Hillary could afford to lose Iowa, given her strong leads in NH, SC, NV, and FL. In political campaigns, of course, two-month-old prognostications are about as valuable as last month's Racing Form. Now it certainly seems plausible, for the first time since late spring, that Obama could overtake her in all these early states, which would effectively end her candidacy.

Complicating her task is the Brave New Politics, in which any mention of an opponent's record or past indiscretions becomes "negative campaigning," no matter how truthful it is. Typically, as Fineman notes, surrogates for Hillary would be popping up all over the political landscape to question some aspect of Obama's experience or history. The Shaheen case illustrates the sissified new rules perfectly: the man merely repeated admissions from Obama himself, and opined as to how they might affect the Senator's chances in a general election. That's not "mud" he was slinging; it was truth.

Politics ain't beanbag, no matter what the latest media poll says. If candidates cannot "attack" their opponents on their records, the electorate suffers for the lack of information.

Certainly Hillary Clinton is subject to more scrutiny than most might be, given the Clinton Machine's long and ugly history of destroying opponents and critics through any means available. Perhaps her being restrained today from making even truthful criticisms because of that past is sweetly ironic.