What might a reasonable, constructive presidential campaign look like? 

To ask the question invites immediate dissent because we probably can't even agree across philosophical or political lines what "reasonable" and "constructive" mean.

But let's try an experiment: Can we at least reach consensus on the sort of debate between now and November that could help us solve some of our problems? I'll let you in on the outcome in advance: Ideology quickly gets in the way of even this modest effort.

Start out by defining goals everyone could rally around. We need to get the economy moving faster and bring unemployment down, an all-the-more-urgent imperative after last week's disappointing jobs report. We want all Americans to share prosperity and to reverse the trend toward widening inequality. We want a sustainable budget where, in good times, revenues more or less match expenditures. And we want an education system that prepares members of the next generation for productive and rewarding lives.

Notice a few things about this list. It does not include social issues. Many Americans on both sides of politics legitimately believe that matters such as abortion, gay marriage, gun control, contraception and religious liberty (I could mention others) are of absolutely central concern. Some of them would reject my agenda at the outset. I'd defend it by insisting that the vast majority of Americans, whatever their views on any of these vexing subjects, want to get to certain basics first. They know the social issues won't go away.

Conservatives might rebel against the way I frame our objectives. In talking about the budget, I do not even bring up reducing taxes. That is because I think the evidence shows that if we are serious about balancing the budget, government needs more revenue. The brute facts of (1) the steady rise in the costs of health care and (2) the aging of the baby boomers mean that we can't just hack our way to a balanced budget without eviscerating programs such as Medicare and Social Security that most Americans want.

Thus a challenge to conservatives: If cutting taxes is really more important to you than fiscal balance, why not just say so? Why pretend that balance matters when your real goal is a sharp reduction in the size of government? Alternatively, if we could agree that revenue is needed, let's argue about the right mix between spending cuts and tax increases, and about which taxes to raise.

And can politicians and commentators stop hiding behind vague promises of "tax reform"? Offer specifics or shut up about tax reform. Let's also agree that slashing programs for poor people -- and I'm one who thinks we should spend more -- won't come anywhere close to resolving our fiscal difficulties.

Job creation is at the heart of the campaign, and it is the issue about which we will have the least clarity. To me (and, I would say, to most non-ideological economists), it is perfectly obvious that rolling back government, both here and in Europe, has been exactly the wrong thing to do in a time of high unemployment. To save words, I refer you to a pile of fact-rich Paul Krugman columns.

The unemployment numbers would be much better without the massive loss of government jobs, and private-sector job growth would, in turn, be higher as those public workers spent money. It would be helpful if conservatives who disagree would offer evidence for why they are so certain that government austerity will make things better.

I'd like to hope we'll get somewhere on education, but as for rising inequality, many on the right don't even think it's a problem. So let's debate over whether greater inequality impedes faster growth or promotes it. Again, I think the evidence shows that when inequality gets out of hand (see 1929 and now), it's a drag on the whole economy. Forgive me for noting that conservatives seem to believe that the rich will work harder if we give them more, and the poor will work harder if we give them less. But let's have it out. Arguing in a serious way about the single question of economic inequality would make all the other nonsense of the next five months endurable.

What I do know is that if we don't use this campaign at least to define the problems we face, we will end up wasting the $2 billion or so this campaign will cost, and a lot of time.

 (c) 2012, Washington Post Writers Group