There were fewer dramatic jabs at Dean than expected, but Lieberman’s was indicative of the state of the nascent Democratic race. Like the night air in his home state of Vermont, the atmosphere is turning a little chilly on the campaign trail for Dean. It will soon get downright frigid. He’s the functional equivalent of a front runner, on track to raise an astounding $15 million in the third quarter of this year, largely due to his success as a Web-based candidate. Historians note that the candidate with the most cash on hand–and the lead in national polls as the primaries start–almost always wins the nomination. Dean likely will have the most money come January. So now his rivals’ aims and hopes are simple enough: to rough him up, and hope he implodes. Here’s a look at the pitfalls, actual and potential, that Dean faces:

‘Flip-flops.’ Dean has risen through shrewd use of the Net and opposition to an increasingly unpopular war in Iraq. But he and his advisers rightly think his best sales point is his image as an antipolitical politician, a country doctor turned governor who boasts of “my directness and my unwillingness to bend” as he bluntly diagnoses all the ills of American life. But the record is more complicated than that, of course, especially as Dean moves from grass-roots obscurity on the Democratic left to a leading contender.

His critics say that the good doctor can bend it like Beckham when he has to. They cite lots of examples. His position on Cuba is one. He had long supported rolling back the U.S. embargo on trade with Fidel Castro’s regime, but recently said that such a step–given recent human-rights violations there–would be a mistake at this time. Another reason for the change: next year’s pivotal primary in Florida. The Cuban-American voters there are Republicans, for the most part, but they are highly organized and always ready to demonstrate on TV.

Some Dean moves–foes call them “flip-flops”–are from right to left. In 1995 he said he liked the idea of raising the Social Security retirement age to 70 to save money. Now he opposes the idea. As the governor of Vermont, he was a strong supporter of NAFTA, the free-trade agreement. Now that he is seeking labor support (and hoping to head off an AFL-CIO endorsement of Rep. Dick Gephardt), he harshly criticizes it. When he –launched his campaign, Dean said he’d run within the federal campaign-finance system, which gives candidates cash if they agree to spending limits. At the time, Dean was worried about Sen. John Kerry’s “opting out” of the system and tapping the accounts of his wealthy wife, Teresa Heinz Kerry. Now, flush with cash and a burgeoning contributor list, it’s Dean who may “opt out.”

Another bend may be around the corner. Dean has been under fire–especially from Senator Kerry–for wanting to scrap even the middle-class portions of the Bush tax cuts. The Dean campaign is now debating internally whether its man should propose his own set of middle-class tax cuts, and has been talking to former Clinton administration economics advisers about just how to shape it.

Byting the hand. Dean’s advisers boast that their campaign isn’t merely Web-based, it’s “open source”: a community created by the digital grass roots. In geek speak, Dean runs Linux, not Microsoft. Everyone can “write code.” That, in turn, gives contributor/supporters (150,000 at last count) a unique sense of participation and ownership. But it also will make it difficult to control the campaign, especially if Dean disappoints the people who were drawn to him in the first place. An “open” system is vulnerable to lurkers and bugs–innocent or malicious. Dean’s top advisers worry that someone will say or do something embarrassing–or worse–in his name. “We have tapped into a force no one can fully control,” said Steve McMahon, a senior strategist. “I hope you guys remember that when something goes wrong.”

Timing is all. Insurgents do best when they strike quickly, and by surprise, just as primary-season voting begins. But Dean is advancing across open country in plain sight of the fortress he wants to take, months before the voting begins. Shaken awake and infuriated by his denunciations of them as corrupt insiders, rivals are fighting back, and will ratchet up their attacks in the months ahead. Kerry, Gephardt and Lieberman–his leading foes–are lifetime politicians and tough customers used to the kind of intense media scrutiny Dean is just beginning to receive. “Reannouncing” his candidacy last week, Kerry chose “courage” for his theme and war experience for his calling card, and supporters of the decorated Vietnam vet made it clear that he was ready for a fight. Establishment Democrats who may have thought the nomination was not worth having–because President George W. Bush looked unbeatable–now believe otherwise. With jobs disappearing and foreign policy a mess, Democrats see an opening, and Dean as too quirky to exploit it.

Mr. Traditional. But for all its Web buzz, the Dean campaign is more traditional than its backers probably know–or than they might like. The top brass: McMahon and Joe Trippi, fortyish veterans who have long been based in Washington; Trippi is in his seventh campaign. The polltaker, Paul Maslin, is a veteran operative, too. Like Bill Clinton, Dean networked his way through the National Governors Association and Renaissance Weekend. He’s now courting labor leaders, ethnic “outreach” staff and members of Congress as enthusiastically as any Beltway insider. The traditional medium of television is next. Dean’s angry persona–perfect for the paradoxically impersonal role as Blogger in Chief–won’t work on TV. He’ll need to show himself up close and personal–and all the oppo guys will be listening closely.