Ultimately, the presidential race is zero-sum contest. One person wins. The other loses. But the constant clashes, quarrels and scraps that lead up to Election Day aren't quite as black and white--despite what the MSM might have us believe.

Take today, for example. The big news is the U.S. Supreme Court's unsurprising 5-4 decision to overturn a 32-year-old District of Columbia law limiting private gun ownership, for the first time expressly extending the Constitution's Second Amendment to private citizens (rather than just militias). The press has portrayed this as a victory for John McCain. The ban--which prohibited residents from keeping handguns at home and required that lawfully registered guns, such as shotguns, be locked and unloaded when stored in the house--has long angered gun-right activists, who said that it infringed on an individual's Constitutional right to keep a firearm in the nightstand for self-defense. Given that these activists are largely Republican--and have clashed with McCain over gun-show restrictions in the past--no one was surprised this morning when the Arizona senator seized on the ruling to slam Obama as a typical gun-grabbing liberal. "Unlike the elitist view that believes Americans cling to guns out of bitterness," he said in a statement, "today's ruling recognizes that gun ownership is a fundamental right--sacred, just as the right to free speech and assembly." Wonder who that "bitter" barb is aimed at.

Meanwhile, the chatterati quickly declared Obama loser of the day. The decision makes a certain kind of sense. As Obama has transitioned over the past five years from liberal Chicago lawmaker to more centrist Democratic presidential nominee, he has struggled to downplay his long record of support for gun-control measures and emphasize his sympathy for gun rights instead. That has created some awkward moments. In 1996, for example, Obama indicated on a pair of Independent Voters of Illinois questionnaires that he supported banning the "manufacture, sale and possession of handguns." Asked late last year about the surveys, Obama's aides said that they were completed by his then-campaign manager, who “unintentionally mischaracterize[d] his position,” and that the candidate himself “never saw or approved” the forms--even though reporters later discovered his handwriting on one of them.

His stance on the D.C. gun ban has been similarly slippery. In 2004, Obama "opposed letting people use a self-defense argument if charged with violating local handgun bans by using weapons in their homes," and in late 2007 his campaign put out a statement saying that "Obama believes the D.C. handgun law is constitutional" (a position he didn't dispute in a later interview). But in February, Obama began to walk back that unambiguous remark, declining at least four times over the following months take a position for or against the constitutionality of the ban. "I confess I obviously haven't listened to the briefs and looked at all the evidence," he said in April. The point, of course, was to situate himself to support whatever the Supremes decided and minimize blowback on a sensitive issue. So when the ruling was finally handed down this morning, Obama (surprise, surprise) embraced the decision--"I know that what works in Chicago may not work in Cheyenne," he said--and spokesman Bill Burton cleared up any lingering confusion by telling ABC News that the campaign's earlier statement declaring the law constitutional "was obviously an inartful attempt to explain the Senator's consistent position." The buck, it seems, stops somewhere over there.

Despite all that fogginess, however, I'm not sure Obama will actually lose this round with voters--or that McCain will win. Imagine, for example, if the court had ruled the other way. Gun owners would be energized. Obama would be forced to declare his support for the ban. The right to bear arms would become a major campaign issue. And McCain would suddenly be able to drive a huge wedge between his opponent and all those bitter, clingy Pennsylvanians. That's a clear win-loss scenario. As it is, Obama gets to reaffirm his broader beliefs, which have, in fact, been consistent all along: that a) individuals have gun rights under the Second Amendment but b) "that individual right is constrained by the rights of the community to maintain issues with public safety." "I don't think those two principles are contradictory," Obama said today. Unfortunately for McCain, the public agrees. A recent Washington Post poll shows that while 72 percent of all Americans consider gun ownership an individual right, a full 58 percent "support a D.C.-like ban on private handguns and trigger lock requirements." So the only way McCain can "win" here--politically, at least--is if swing voters (who largely concur with Obama on the underlying issues) absorb the whole confusing chronology and decide that it exposes some sort of character flaw. Maybe it does, maybe it doesn't. But very few people will sit still long enough to find out.

Team McCain's best bet? Using Obama's gun-shyness as a plot point in a larger narrative. They're already off and running. The idea, as Jonathan Martin reports, is to "paint Obama as a conventional politician who always takes the safe and easy political road, then amplify the distinction by framing McCain as a patriot, somebody who has put sacrifice above self."  On a conference call this morning, Kansas Sen. Sam Brownback claimed that Obama's recent maneuvers on guns, FISA and campaign finance "reflect a willingness as the campaign changes from a primary to a general to change on positions," while McCain foreign policy guru Randy Scheunemann charged that "the most important issue [for Senator Obama] is the political fortunes of Senator Obama." Of course, McCain has his own issues with flip-flopping. But defining Obama as conventional candidate whose politically advantageous calculations contradict his change-agent image strikes me as McCain's most (and perhaps only) promising line of attack. Unfortunately for him, though, the bell won't ring on that particular round until Election Day.

UPDATE, June 27: The New Republic's Noam Scheiber makes a great point about McCain's "typical pol "attack:

Obama has such a strong tail-wind behind him that he'll win if "typical pol" is the worst thing you can call him. (He'll still be a typical Democratic pol, after all, which voters say they strongly prefer this year.) The only way he loses, I think, is if voters get the impression he's somehow un-American, un-patriotic, out of the political mainstream, or unable to keep them safe. To the extent that it draws attention from these insinuations, the "typical pol" charge may even help him somewhat. Thanks to his race, his eloquence, and his relative youth, Obama's just never going to come across as completely typical. In some sense the bigger risk is not being typical enough.