Up Next: Clinton Attacks Obama

In presidential politics, national front-runners of Hillary Clinton 's stature are allowed one loss like the one she suffered tonight in Iowa.

Walter Mondale and George W. Bush, for instance, bounced back from humbling New Hampshire defeats, and George H.W. Bush rallied after finishing third in Iowa in 1988. But none of those big-name front-runners tempted fate by falling short in two straight major contests. That dramatically raises the stakes for Clinton in New Hampshire, where a loss will put her in uncharted territory, as overwhelming front-runners go.

The good news for Clinton is that she has a well-oiled machine in place in New Hampshire, where she's loaded up on endorsements and where her operation is guided by some of the state's top political pros. There is also residual goodwill in the state for her husband, who will undoubtedly now ask Granite Staters to help make his wife another "Comeback Kid."

The bad news is that the race in New Hampshire was already tight before Iowans headed to their caucuses. Like all other Iowa winners, Barack Obama will receive a quick boost in the New Hampshire polls, and the Clinton campaign will only have five days to bring him back to earth. Plus, unlike past underdogs, Obama isn't scrambling to catch up with the front-runner when it comes to money and name recognition. He is already a well-established and well-funded candidate.

If Obama can hand Clinton back-to-back defeats, there is no telling what damage will be done to her standing in other states. There simply is no precedent in modern presidential politics for the clear national front-runner to be considered the clear loser in the first two states.

To avoid that fate, bet on one thing: The Clinton machine will go negative.

Already, there have been reports that Clinton has readied an attack ad for the New Hampshire airwaves, going after Obama over the details of his health care plan. There may be others in the days ahead. This is the same game the Clintons played the last time their White House ambition was in peril, 16 years ago when Paul Tsongas unexpectedly blocked their path. Bill Clinton then buried him with a wave of ugly—and misleading—attacks.

Obama, though, is better known and conjures warmer feelings than Tsongas. And Hillary, by contrast, doesn't have the innate ability to connect with voters that her husband did. It is certainly conceivable that the 2008 version of Clinton attacks will not resonate the way the 1992 version did.