Mr. Edwards' surprisingly close second-place finish to Mr. Kerry in Wisconsin, coupled with former Vermont Gov. Howard Dean's withdrawal, gives the amiable North Carolinian his best chance yet to convince voters why he, not Mr. Kerry, should be nominated, and none too soon.
Mr. Edwards provided a preview in the Wisconsin primary of the strategy he likely will use: pointing out their differences on key issues such as trade, health care and cutting the federal deficit while seeking to maintain the positive, upbeat posture that has been central to his survival in the race so far.
Having won only one primary heading into the Super Tuesday tests on March 2, Mr. Edwards must avoid comparing his record with that of Mr. Kerry too aggressively to the detriment of his own nice-guy image.
Conventional political wisdom holds that when you're as far behind as Mr. Edwards, it's imperative that you hit your opponent with all you've got. That most often means "going negative." Most political consultants contend that while voters say they don't like candidates doing so, it seems to work.
In that sense, Mr. Edwards' demeanor so far offers a good test of whether, in the crunch of a one-on-one contest, a trailing candidate can stay on the high road and win. As recently as 2000, Democrat Bill Bradley tried to do that, inviting opponent Al Gore to join him on that road. He got his head handed to him.
In the Iowa caucuses that year, Mr. Gore brushed aside the overture and ambushed Mr. Bradley on an obscure Senate vote Mr. Bradley had cast that unjustly painted him as anti-agriculture. Mr. Bradley never recovered as Mr. Gore continued to attack, soon driving him from the race.
Complicating Mr. Edwards' challenge to Mr. Kerry is that the issue differences between the two Democrats have been relatively minor so far. At the same time, there is nothing Mr. Edwards can say to counter Mr. Kerry's 19 years in the Senate and his stature as a decorated Vietnam war hero, which eclipse Mr. Edwards' five years in the Senate and no military service at all.
Both Democrats are rich men, but Mr. Kerry's wealth is largely inherited through his own patrician family and his wife, whereas Mr. Edwards' is self-acquired as a successful trial lawyer. He weaves an appealing saga for voters as the son of a mill worker who made his own way through college and law school and got rich by winning lucrative verdicts on behalf of poor folks.
The most apparent other difference between them has been stylistic -- Mr. Kerry sober, serious and short on humor and warmth compared to the boyish, buoyant and eloquent Mr. Edwards. But this stylistic edge has brought Mr. Edwards a primary victory only in his native South Carolina, along with several second-place finishes.
Mr. Edwards' runner-up showing to Mr. Kerry in Wisconsin, as impressive as it was, can be misleading about his chances in the primaries and caucuses ahead. The Wisconsin primary was open to all voters regardless of party. Exit polls indicated Mr. Edwards beat Mr. Kerry among Republicans and independents, who will be shut out of the 22 closed Democratic contests remaining, including seven on Super Tuesday.
In 2000, Republican maverick Sen. John McCain upset then-Gov. George W. Bush in the open New Hampshire GOP primary with strong Democratic and independent support. But then he ran into a string of closed contests that sealed his fate against Mr. Bush, the establishment party candidate. Mr. Edwards could face a similar hurdle.
As the well-heeled Mr. Kerry campaigns everywhere, Mr. Edwards is picking his spots, already focusing this week on five of the 10 Super Tuesday states -- New York, Georgia, Minnesota, Maryland and Ohio. Mr. Edwards will be pitting his trade and economic messages against Mr. Kerry's experience and his claim, backed up by the Wisconsin exit polls, as the more electable candidate against President Bush.
It may be too late for Mr. Edwards, but he's not acting that way. He's even looking beyond Super Tuesday to March 9, when four Southern states -- Texas, Florida, Louisiana and Mississippi -- vote.
In the immortal words of Yogi Berra, it ain't over till it's over.
Jules Witcover writes from The Sun's Washington bureau. His column appears Mondays, Wednesdays and Fridays.