Do either Barack Obama or Mitt Romney really want to win this election?

Neither wants to lose, certainly, or for the other guy to win. They are both highly competitive. History judges one-term presidents as failures. Romney has spent the better part of a decade pursuing the quest on which his father fell short.

But as they punish themselves and pummel each other in this joyless, grinding campaign, you have to wonder: How delighted will the winner be when he wakes up Wednesday, Nov. 7? What will he hope to accomplish over the next four years?

It has long been clear that Obama merely tolerates many aspects of his job that some of his predecessors (well, Bill Clinton, anyway) relished: schmoozing with other pols, hobnobbing with other leaders, mingling with voters. And the sweeping promise of his first campaign, to transcend politics and transform Washington, has been deflated by the Great Recession, tea party-fueled GOP intransigence and his own timidity at pivotal moments. Four years on he is waging a diminished, conventional campaign combining appeals to reliable interest groups, bromides about the middle class that will provide no useful mandate for governing, and, above all, the demeaning of his opponent.

For his part, Romney has remodeled himself so thoroughly since his days as a moderate Massachusetts governor — when he supported universal health care, abortion rights, cap-and-trade solutions to climate change and a ban on assault weapons — that it’s impossible to know what inside him remains real, if anything. His campaign is an uninformative mix of insult and cliché, in his case about the greatness of America and its job creators.

If, as many suspect, Romney’s true inclination as president would be to return to his Bain Capital self, managerial and problem-solving, he might find himself as frustrated as Obama. Democrats are preparing to challenge his legitimacy, on grounds of Republican-imposed voter ID laws with disparate racial impact, while many Republicans will remain more interested in purity than progress. If on the other hand he has truly converted to the doctrine that government revenue must perpetually decrease, his presidency will drown in red ink, and bring the country down with it.

From what Obama has done and said the past four years, we have a clearer sense of what he would attempt in the part of the job he does enjoy — shaping and implementing policy — if he had a second chance. But he’s likely to be as constrained by Congress in the next four years as he has been in the past two, and even more constrained by debt and deficits. Recognition of those limits may be one reason that he has yet to present much of a second-term agenda — and that the prospect of a second term has to be bittersweet.

So the only motivation that surfaces clearly for voters is the desire to stop the other side — the conviction that the opponent’s agenda would be dangerous. If the pattern holds after the conventions, this may be what propels voters to the polls in November.

Democrats disappointed in Obama for a variety of reasons nonetheless will coalesce behind a nightmare vision of a Romney presidency: a Scalia-dominated Supreme Court, a constriction of abortion and even contraception rights, a dismantling of Medicare and a rollback of Obamacare. Republicans with little love for Romney will similarly respond to his alarms of an ever-metastasizing federal government and a strangling of individual freedom in a second Obama term.

It is a blocking election. The candidates give us little sense of what they would actually do in office. Neither tries to rally Americans behind a positive vision and agenda for the next four years. The rationale instead is the frightening specter of an enemy win.

That may be enough to get people to the polls, but it helps account for why the election is so dispiriting. Voters might be as unhappy on Election Day as the winner will feel the morning after.