At 6:45 this evening, John Edwards strode on stage at the Van Andel Arena in Grand Rapids to the sounds of Bruce Springsteen's "The Rising." "The reason I am here tonight is because the Democratic voters of America have made their choice," he said. "And so have I." His choice? Judging by all the "Change You Can Believe In" signs shimmering in the crowd--and the lanky black guy standing with him onstage--it was (drumroll, please) Barack Obama. Henceforth, the heavens opened, the American people wept and Chris Matthews and Co. began to prattle endlessly about how Edwards will help Obama win over those stubborn "white, working-class voters" who've been bedeviling him in the primaries.

The frantic coverage is a given. But will the Edwards endorsement actually change anything? It's unlikely--and the reason is timing. If the former North Carolina senator had taken a real risk and sided with the Illinois senator back when someone not named "Barack Obama" had even the remotest chance of clinching the nomination--say, before Super Tuesday, or Ohio, or even Indiana--he might have helped his blue-collar base overcome its suspicions, vote for his chosen candidate and bring this interminable battle to an end. But after Hillary Clinton failed to meet her own expectations in Indiana and North Carolina on May 6, every sentient life-form on Planet Earth pretty much agreed that the former First Lady wouldn't be representing the Democratic Party in November. From that point on, Edwards endorsing Obama was a foregone conclusion. Edwards is a Democrat. Obama's the Democratic nominee. It had to happen eventually.

All of which is just to say: there's not much that an Edwards endorsement does for Obama right now that it wouldn't do on, say, June 4. (Besides shifting the storyline from "Obama isn't winning the Bubba vote" to "maybe he will.") The "white, working-class" voters of West Virginia can't recast their ballots. And Clinton will still clobber Obama--think 25 points--in Kentucky on Tuesday, even if Edwards joins him on the stump. With the primaries essentially over, Edwards is basically stepping into his inevitable general election role--a credible liaison to blue-collar America who seeks to sway skeptics by saying "I'm one of you and here's why I support this guy"--a few weeks early. When I mused this morning about why seven percent of West Virginians supported Edwards in yesterday's primary, a reader from West Virginia named "mountaingal" wrote in to explain. "I can tell the difference between pandering (Hillary downing shots), charismatic fluff (Obama's rhetoric) and honest-to-goodness conviction. [Edwards] understands where we come from... His 'son of a mill worker' message... resonates with those with similar upbringings." For that reason, Edwards will undoubtedly help bring Democratic voters like "mountaingal" into the Obama fold by November. But again, he was always going to do that. Whether he starts today or in two weeks doesn't make much of a difference.

That said, it's worth wondering how many mountaingals and mountainguys Edwards can "deliver" for Obama on Election Day--and whether those gains would actually help Obama overcome John McCain. The signs from his brief 2008 bid are somewhat encouraging. In South Carolina--the only remotely "Appalachian" state where Edwards competed--he won white men, whites over 30 and whites overall, despite earning only 18 percent of the vote to Clinton's 27 and Obama's 55. The only problem? Edwards has already attempted a similar feat on the national stage--and it didn't work out so well. In 2004, John Kerry captured only 41 percent of the white vote--not enough to defeat George Bush--and lost in Edwards' home state of North Carolina by a dozen points. Back then, Edwards wasn't just another surrogate; he was Kerry's running mate. So his record is mixed at best.

Tonight, Edwards opened his remarks with reams of praise for Clinton--and an explicit call for unity. "When this nomination battle is over--and it will be over soon--brothers and sisters, we must come together as Democrats and in the fall stand up for what matters for the future of America," he said. "We are a stronger party because Hillary Clinton is a Democrat." A gracious and necessary message, but even here it's unlikely that Edwards' timing will prove particularly consequential. Clinton is determined to battle at least until Montana and South Dakota vote on June 3, and any effort to declare a victor before then will only encourage her supporters to dig their heels in deeper. Far from changing any minds--other than those of a few fence-sitting superdelegates, perhaps--tonight's endorsement will merely reinforce the existing contours of the contest. The Democrats will come together eventually, and Edwards will do his duty. But until then, he--like the rest of us--is just going to have to wait.