Perhaps it was the expectations raised by his far more eloquent appearances at earlier conventions, or maybe it was the modest ambitions he embraced, or that he labored in the shadow of Bill Clinton's rousing defense of his administration, but even the most hard-core Democrat would have to concede that President Barack Obama's acceptance speech to his party's national convention was neither especially memorable nor ambitious.

If the message of the Republican National Convention can be distilled to, as Mr. Clinton memorably described it, "we left him a total mess, he hasn't cleaned it up fast enough, so fire him and put us back in," then perhaps the Democratic National Convention might be boiled down to "we're doing the best we can with this mess so be patient, and, oh, by the way, that other guy would be a lot worse."

In short, Mr. Obama gave a "stay the course" talk to a country that isn't particularly satisfied with the direction the nation is headed. It's not hard to understand why he chose to avoid the kind of lofty goals he set for himself in 2008. Older and maybe even wiser than four years ago, but more tellingly locked in a tight race where a relative handful of undecided voters in swing states could decide the election, the incumbent chose to play it safe, much as Mitt Romney did one week earlier in Tampa.

If anyone was hoping to get a clear picture of what another four years in office might involve, they certainly didn't get it — aside from "visions" of creating 1 million manufacturing jobs, recruiting 100,000 math and science teachers and reducing budget deficits by $4 trillion. How those things would be possible, particularly with a highly partisan divided Congress, was never detailed.

Instead, like so much of what happened this past week in Charlotte, the candidate seemed more interested in reacting to Republican criticisms than staking out new ground. Mr. Obama and the Democrats played defense, sometimes very effectively (Mr. Clinton's speech is likely to have an active video life on the Internet for weeks to come) and sometimes less so — if, for instance, voters don't realize that the Republicans distrust government and the Democrats distrust unregulated Wall Street fat cats, then they weren't paying attention to the proceedings.

What is worrisome about this trend is that neither candidate seems to be offering an agenda so much as a promise that he won't be like the other guy. Mr. Romney is counting on voter discontent with the economy while Mr. Obama is banking on fears of a return to the economic policies of George W. Bush with tax cuts favoring the rich and a laissez-faire view of government regulation. And without that clear agenda, it's difficult to see how Washington will be much changed by the election. Mr. Obama's speech, if anything, amounted to a promise that it wouldn't.

Conspicuously absent from the discussion at either convention was the impending "fiscal cliff" and the possibility of a dramatic increase in taxes coupled with significant cuts in spending resulting in another economic recession. Can the next president negotiate his way out of that mess? How can he claim to be representing the will of the electorate if neither candidate ever articulated exactly what he intended to accomplish once elected?

That's not to suggest there aren't sharp differences between Mr. Obama and Mr. Romney. From the Affordable Care Act and women's reproductive health to Medicare and tax and budget policy, the contrasts are striking, perhaps even representing "the clearest choice of any time in a generation," as President Obama claimed in his acceptance speech. But it appears the nation is just as sharply divided on those issues as the candidates are themselves.

Mr. Obama is likely to get a bounce in the polls this week, if only because Mr. Clinton's fact-filled defense of his term was too compelling to be ignored. But the bounce probably won't be big or lasting. He is no longer the rock star of 2008 when excitement over his candidacy drove record numbers to the polls. But he has to hope that what he offered in Charlotte — a more experienced, more tempered candidate of more modest ambitions — is what voters are looking for right now.