The first casualty of war, it is said, is truth. The first casualty of close political campaigns, it seems, is perspective. Case in point: The singularly unconstructive but increasingly intense exchange between the Clinton and Obama campaigns on health care reform, (with TV ads by Clinton in the works), which can best be summarized as dueling claims that “my plan is bigger than yours.”

The general issue is whose plan will leave fewer people uninsured. The particular issue is whether Hillary Clinton’s idea that a mandate requiring everyone to have insurance will boost insurance coverage more than would Barack Obama’s plan that mandates insurance for children only. Before you give what may seem like the obvious answer, recall that while Obama would enforce his mandate by requiring parents to show insurance coverage for their children when they enter school, Clinton has not explained how her general mandate would be enforced. Neither has explained in detail how much assistance will be given to make insurance affordable and therefore sustainable. And Obama acknowledges that he would be open to a broader coverage mandate if needed to achieve universality.

So, now, answer the question--which plan covers more people?

The honest answer is that neither plan covers anyone. Plans don’t cover people, legislation does. This response is not a cute evasion, but a warning that before candidates can convert their ideas into legislation, they have a few other jobs to do. They must first win a nomination, then an election. After taking office, the winner must negotiate with a Congress that will probably be nearly as divided as the current one is. The then-president will have to nudge fractious senators and representatives representing diverse interests to develop a bill that can win a majority in the House and sixty votes in the Senate. The resulting bill, if it ever is passed, will in some measure be influenced by the president, but it will be written by members of Congress. It will likely bear only a passing resemblance to the vague campaign releases now being picked apart by analysts as if they were dealing with well-specified legislation.

Vagueness, let’s be clear, is a virtue, not a fault, in a campaign document. Eight years ago, former Senator Bill Bradley, who was also running for president, was advised in a closed-door meeting by three sympathetic advisers not to put forward a detailed health care reform plan. Details, the advisers warned, might endear him to analysts and the press, but would give his primary opponent, Al Gore, and a Republican opponent in the general election many targets at which to shoot. Bradley, determined to be responsible, rejected this advice and put forward a detailed program. The picking apart promptly began and contributed to Senator Bradley’s early defeat.

The still relatively vague plans each Democratic candidate has advanced should be treated not as if they were the law of the land, but as general statements of intent on how they would approach a critical national issue. The striking characteristic of the statements of the three leading Democratic candidates is not their differences but their similarity. All have issued lengthy position papers that are short on detail but make clear beyond serious doubt that they regard health care reform as the most important domestic issue they will confront. All favor comprehensive coverage. All want to use a mixture of public and private insurance to achieve that coverage. All support a host of cost-reducing measures to help pay for the greatly increased subsidies to low- and moderate-income households.

The Democrats’ positions contrast markedly with the almost cursory but negligibly varying statements on health care from all of their potential Republican opponents. The Republicans uniformly repudiate increased government involvement in health care (other than Senator McCain, who would expand Veterans Affairs health services). They all endorse modifications in the tax treatment of employer-financed health insurance to encourage individual, rather than group, insurance. All would rely on reforms to increase market incentives under which individuals would have more responsibility to police health prices and quality.

In other words, a chasm separates Republicans and Democrats on the issue of what to do about the U.S. health care system. And very little separates the major candidates within each party.

In this situation, what should Democratic primary election voters make of the dueling press releases and expert statements that each side has invoked on the desirability of an individual mandate? The answer, I believe, is close to nothing. Here's why. First, the positions of the candidates are barely distinguishable. Second, if elected, no Democrat will be able to shove a health care reform plan through Congress without major modification. Third, all would call on a similar set of advisors with broadly similar views. (Do not doubt that most analysts advising each Democratic candidate would gladly serve in the administrations of their current rivals!) Primary voters should not base their votes on the negligible differences that distinguish the campaign statements of the candidates on health care. Rather, they should base their votes on their judgments regarding the capacity of each candidate, if elected, to unify their own party and to reach across the aisle to achieve the bipartisan cooperation that will be necessary to enact major health care reform. The current analytical squabble is a diversion. As a certified policy wonk, I fully understand the seductions of these debates. Models. Statistics. Oh, boy! But having lived through way too many of these arguments, I also understand that winning them has nothing to do with getting elected and governing effectively. Let’s keep our eye on the ball.

Henry J. Aaron is the Bruce and Virginia MacLaury Senior Fellow in the Economic Studies Program at the Brookings Institution.

By Henry J. Aaron