Last Saturday in Springfield was a picture-perfect day for the Obama campaign. The selection of Obama’s running mate had been squeezed for every possible drop of anticipation, drama and media frenzy.

[IMGCAP(1)]All was going according to plan at the convention kickoff rally when presumptive Democratic presidential nominee Sen. Barack Obama (Ill.) inexplicably bungled his introduction of running mate Sen. Joseph Biden (Del.), calling him “the next president.” Taking a cue from his leader, Biden proudly followed suit by referring to Obama as “the next president of the United States, Barack America.”

This not the way to begin a nominating convention that needs to give Obama a bounce — a big bounce. The current political environment gives Democrats a substantial edge, yet almost three months after securing the nomination, Obama continues to underperform, running well behind the Democratic generic ballot advantage.

Despite switching a long list of liberal positions in an obvious move toward the center, he has failed to create a significant margin between himself and presumptive Republican nominee Sen. John McCain (Ariz.). Democrats are concerned, and they should be.

The context for the fall election has changed significantly. Both McCain and Obama succeeded in their respective primaries, in large part, because of their positions on the Iraq War.

But, as the surge has succeeded and there appears to be light at the end of the Iraq tunnel, the economy has superseded the war as the top issue. Democrats had counted on voters’ anti-war feeling to carry them to victory in November. As that issue has faded, they have turned to the faltering economy as a fallback strategy.

While they still have an advantage over McCain and Republicans on the economy, polls show their lead is shrinking, and increasingly, they find themselves on the wrong side of the most critical element in the economic rubric of issues: energy.

Democrats can thank $4 a gallon for turning their election strategy on its head. Much to their dismay, Obama and Hill Democrats have now discovered that following “uber-green” Al Gore and his “handmaiden” Speaker Nancy Pelosi (D-Calif.) down the “no drilling” path has put them squarely at odds with the vast majority of voters.

Democratic Members of the House and Senate can read polls, too, and are, no doubt, still waiting for Senate Majority Leader Harry Reid (D-Nev.) and Pelosi to explain why the Democratic Congress’ job-approval numbers are lower than the president’s. The public was unhappy with Congress before energy emerged as the central economic concern, but Republicans had not given them a reason to reconsider the 2006 election.

The energy issue, led by House Minority Leader John Boehner (R-Ohio), former Speaker Newt Gingrich (R-Ga.) and McCain, has given voters a reason to consider Republicans again.

While neither campaign has developed a clear economic message, McCain’s support for increasing domestic energy is far closer to the views of the majority of Americans. Most polls show that about 70 percent of voters support increased drilling.

It’s not surprising that Obama, reinforced by most of the Democratic Party leadership, has resorted to a combination of classic Democratic class-warfare rhetoric (which didn’t work for Gore), personal shots and a one- dimensional message of change that is wearing thin.

Given Obama’s issue flip-flops over the past few weeks, Americans don’t really know what kind of change he offers other than the fact that he isn’t George Bush and, according to every Democrat including Obama who will hit the podium this week, John McCain is. Choosing the consummate Washington insider as his running mate reflects the obvious problems Obama is having with his brand.

He wants to continue to claim the mantle of change, but polls show people are simply not convinced he’s ready to be either commander in chief or chief diplomat. So, he picks Foreign Relations Chairman Biden in an effort to close the experience gap and runs headlong into his own outsider image of change, so carefully crafted during the primaries.

Biden brings a quick wit (which gets him into trouble on occasion) to the campaign, and that will make him a formidable opponent, particularly in the debates. He also will help with Catholics, a key voter group that Sen. Hillary Rodham Clinton (D-N.Y.) won in the primaries by sizable margins.

But his sharp criticism during the primaries of Obama’s lack of experience only reinforces the underlying source of Obama’s underperformance, and when it comes to party unity, he simply isn’t Hillary Clinton.

Add to voter wariness their impatience with the kind of personal, nonissue attacks Obama launched last week over McCain’s “housing” gaffe and the outcome of the convention becomes even more important.

I suspect hardly a speaker will leave the stage without a crack about McCain’s homes or allusions to his age. That is exactly the kind of attack politics voters don’t want, and Obama promised to reject, putting him once again in conflict with his brand and giving the McCain campaign justification for raising Rezko, Wright, Ayres and other Obama skeletons as issues.

The Obama campaign is off track and off message, which is why the convention has become so crucial. Clearly frustrated by his lack of progress, Obama is discovering, as are Pelosi and Reid, that being the “anti-Bush” isn’t enough. Neither is simply being for some obtuse promise of “change.”

To be successful, the Democratic convention must convince voters that a leftist doctrinaire is really just like them, that his running mate’s earlier criticism of his lack of experience no longer applies, that Hillary and Bill Clinton are really on board, that Obama’s new attack strategy doesn’t conflict with his brand, and that Democrats are really in tune when it comes to energy and the economy.

That’s a tall order.

David Winston is president of the Winston Group, a Republican polling firm.