Likability matters in presidential politics, but it’s not trump in tough economic times. When their pocketbooks are hurting, voters cast about for alternatives. A doleful-days campaign can still be a close tug-of-war between competing visions. Other times, however, frustrated voters are ready to try something radically different, as long as its champion seems reasonable. That was the case in 1980, when the land slid to Ronald Reagan after his reassuring debate performance with Jimmy Carter.

If Election 2012 is decided mostly on personality — something highly unlikely this time around — Barack Obama will probably win a second term. Contrariwise, if the vote is simply a referendum on Obama’s economic performance, Romney may well prevail.

In fairness to Obama, the president took office under extremely difficult economic circumstances. His jobs record, meanwhile, is better than he generally gets credit for. The nation has now recovered all the private-sector jobs lost during his presidency; his on-my-watch employment deficit comes only because of the hundreds of thousands of public-sector jobs that have been cut. Still, the economy hasn’t come back strongly enough to reduce the unemployment rate convincingly, and now there’s a real worry that things could be slowing down again.

It’s easy to see how much that issue cuts. Voters view Obama as more understanding of, and sympathetic to, the average person’s plight. But because Romney is seen as possessing economic know-how, he’s in a neck-and-neck race with the president.

Part of Obama’s problem is that voters don’t have a clear sense of what he’s trying to do. After conducting a recent Denver focus group for the Annenberg Public Policy Center, pollster Peter Hart reported that “participants have no idea where we go from here. . . There is no road map, no program, and no conviction of where the president wants to lead the country.”

There are plenty of big, unanswered questions.

That’s ideal for Romney, who wants to campaign against Obama's record rather than on his own ideas. Speaking to a convention of Latino officials Thursday, the Republican candidate summed up his approach perfectly: “This is an election about the future of America. I would ask each of you to look at the last three and a half years and ask whether we can do better.” Romney, in other words, hopes to seed a Reagan-Carter dynamic.

That’s something Obama can’t afford — and that explains his camp’s increasing efforts to highlight the holes in Romney’s proposal. And let’s be clear: There are plenty of big, unanswered questions.

For example, Romney has called for both 20 percent across the board tax cuts, at a cost of about $5 trillion over a decade, and for a balanced budget.

But how would he accomplish that? Romney has sidestepped the difficult details by talking vaguely about closing tax loopholes and limiting deductions, and by asserting that he’d reduce federal spending, now at about 24 percent of gross domestic product, to 20 percent of GDP. But he hasn’t identified tax expenditures of anywhere near the magnitude his plan would require. Nor has he proposed a realistic range of programs cuts. He’s employed the same skip-the-crucial-details approach on his proposals to rein in Medicare spending and means-test Social Security.

His vagueness is obviously calculated. Indeed, Romney himself has noted that he hasn’t provided enough details for his fiscal plans to be properly analyzed or “scored.” So why not provide them? Romney’s answer: Those details will have to be worked out with Congress.

That’s silliness on stilts. The real reason he’s keeping things foggy is because he doesn’t want to give Obama any more targets than absolutely necessary. Why? Because he wants a referendum on Obama's record, not a serious consideration of their competing ideas.

Team Obama's challenge, then, is to do what Romney won’t: To make clear to voters what the real-world consequence of Romney’s plans will be. In other words, to resist his rival’s attempt to make this election all about the incumbent and instead turn it into a considered choice between their two competing plans for the future.

Romney won’t want that, of course. But it’s something information-hungry voters should welcome.