DES MOINES — The announcement of John Mellencamp’s Wednesday night show to cap the Iowa caucus campaign of John Edwards did not provoke the media frenzy that accompanied Oprah Winfrey’s Des Moines tarmac tap on behalf of rival Democrat Barack Obama.

For this, Edwards should be thankful.

Obama stalled in the Iowa polls after Winfrey visited the state on his behalf early in December. With hours to go before the caucusing begins, he’s essentially where he was a month ago — ahead in many polls, but mainly on the strength of young and independent voters who may or may not show for caucuses that traditionally have been dominated by older and more partisan Democrats.

In contrast, national front-runner Hillary Clinton, who fumbled repeatedly in November and early December, and Edwards, who had been written out of the race by some pundits, appear to have regained their positions going into tonight’s voting.

Obama misread Iowa. He bet on style over substance in a state where activist Democrats take seriously the definitional role their play in the nominating process. The senator from Illinois, who had so much momentum at the beginning of December, calculated that the Hawkeye state might be locked up by a recommendation from a multi-media persona whose entry into presidential politics came off a little like the launch of a new “project.”

None of this means that Obama should be counted out in Iowa. He has spent far more money than the other candidates on slick TV ads, he has hired some of the best caucus strategists and his campaign is tossing every charge and claim it can muster into a drive to blunt the momentum that has belonged to Edwards since he dominated the last pre-caucus debate between the Democratic contenders.

Obama is still the safe bet to win tonight.

But, despite his many advantages, the Illinoisan could well finish behind Edwards.

That’s because the 2004 Democratic nominee for vice president has waged a dramatically different campaign than Obama’s feel-good effort. Where Obama has run the softest sort of campaign, Edwards is mounting a edgy, muscular effort that owes more to the memory of Paul Wellstone or the sensibilities of Ralph Nader than to the smooth triangulations of Bill Clinton or the not-so-smooth compromises of John Kerry.

Edwards has fought his way back into contention with aggressively populist positions, anti-corporate rhetoric and a campaign that eschews glitz for grit — as evidenced by a grueling 36-hour marathon campaign swing that includes the Mellencamp visit. Necessarily, the former senator from North Carolina opts for a different sort of celebrity than the other contenders.

So it is that Mellencamp comes to Iowa to close the Edwards celevrate the Edwards campaign with a “This Is Our Country” rally at the not-exactly-Hollywood Val Air Ballroom in West Des Moines. (In case anyone missed the point here, tickets were distributed not through some slick internet delivery system but from the United Steelworkers Local 310 hall.)

Where Winfrey brought a big name but little in the way of a track record on issues that are fundamental to the rural and small-town Iowans who historically have played a disproportional role in tonight’s caucuses, Mellencamp is more than just another celebrity taking a lap around the policy arena.

For a quarter century, the singer has been in the thick of the fight on behalf of the rural families he immortalized in the video for “Rain on the Scarecrow,” his epic song about the farm crisis that buffeted Iowa and neighboring states in the 1980s and never really ended.

Mellencamp has not merely sung about withering small towns and farm foreclosures. As a organizer of Farm Aid, he has brought some of the biggest stars in the world to benefit concerts in Iowa and surrounding states, and he has helped to distribute the money raised at those events to organizations across Iowa.

Farm Aid is nonpartisan. It’s not endorsing in this race. But Mellencamp is. The singer, who this year will be inducted into the Rock and Roll Hall of Fame but whose music remains vital enough to have earned a 2008 Grammy nomination for Best Rock Vocal Performance, was lobbied for support by other campaigns, especially Clinton’s. But he has a long relationship with Edwards. He has an even longer relationship with the issues that Edwards is talking about. Indeed, his credibility is grounded in the recognition that Mellencamp has repeatedly taken career-risking anti-war, anti-racist and anti-poverty stances that other celebrities of his stature tend to avoid.

What matters, of course, is the fact of that credibility — and the fact that it is so closely tied to the farm and rural issues that have meaning even in the more urbanized regions of Iowa. That is why, if there is an endorsement that is going to have meaning with the people who drive down country roads to attend caucuses Thursday night, it could well be that of the guy who proudly sings that, “I was born in a small town…”