President Obama’s campaign kickoff mostly received the obligatory friendly coverage that most obligatory events do. However, it was impossible to miss the big challenges that confront the president’s reelection campaign and that limit his options and message.

In 2008 it was the Democrat’s time to win; Obama was fresh and he could get away with slogans and platitudes. He has already tried to pitch some of his second-term plans, but all he has been able to say so far include vague calls for things like immigration reform, dealing with “the long-term challenges of energy independence and climate change” and helping “people who don't have work find work.” Blah. Only the most compliant, committed followers could make these vapid pledges work as applause lines.

But Obama in the White House hasn't delivered the results that would allow him to call for a second act with bold initiatives or a robust agenda. His most honest pitch is to beg for patience.

The campaign opened with a predictable attack on Mitt Romney as a businessman. Even that is a two-edged sword. Obama will attack private equity, but he can't attack private investment. He can make claims about Romney’s allegedly flawed business perspective, but by any measure Romney was a success, and giving someone with real business experience a chance would certainly be a contrast with Obama. Even with an administration that hasn't been willing to find positions for many business leaders, he can't be openly anti-business. Too many voters still count on them.

Meanwhile, voter registration among two of Obama’s core constituencies, African Americans and Hispanics, is down sharply. And the president reinforced the idea that he suffers from diminished enthusiasm by drawing a smaller-than-expected crowd to his first 2012 campaign rally. More blah. Somewhere, a campaign advanceman is in trouble.

Platitudes won’t convince the worried undecideds, Romney isn’t a good villain, and more-of-the-same isn’t good enough to enthuse the ideological followers he attracted in record numbers to his campaign in 2004.

The campaign is a marathon, not a sprint, but the president is off to a slow start.