Yesterday M. Simon opined that because the Heller decision was only 5-4, the gun issue might very well become important in the fall election.
While I can’t predict that far in the future, what prompted this post is that I’m still not certain which candidate will benefit more in the long run from the Heller decision.
Eric S. Raymond gives some excellent reasons why McCain will benefit from the Heller decision:

…I’m certain that right now he’s [Obama’s] wishing the Heller ruling had come down 7-2 or better and he didn’t have to deal with what McCain is going to do to him over this issue.
I’ll finish by re-quoting McCain’s delicious, deadly zinger:
“Unlike the elitist view that believes Americans cling to guns out of bitterness, today’s ruling recognizes that gun ownership is a fundamental right — sacred, just as the right to free speech and assembly,”
The sting here isn’t just McCain’s “sacred right” appeal to gun owners, it’s the way he links Obama’s anti-firearms record to the sense of elitism, entitlement and disdain for traditional American values that radiate from the man. These traits play well in Berkeley and on the Upper West Side, but they lose national elections.
Like John Kerry in the last election cycle, Obama increasingly looks like a man who knows the price of arugula but the value of nothing. And if John McCain can convince voters of that, he’ll not just win the general election — he’ll actually deserve to.

On the other hand, George F. Will thinks Obama benefits.

Obama benefits from this decision. Although he formerly supported groups promoting a collectivist interpretation — nullification, really — of the Second Amendment, as a presidential candidate he has prudently endorsed the “individual right” interpretation. Had the court held otherwise, emboldened gun-control enthusiasts would have thrust this issue, with its myriad cultural overtones, into the campaign, forcing Obama either to irritate his liberal base or alienate many socially conservative Democratic men.

If they’re both right (and depending on how things play out, they could both be right), that would make this issue unpredictable, which might take it off the table after all — if for different reasons than the ones given by Taegan Goddard yesterday:

By re-affirming that Americans have a right to own guns for self-defense and hunting, the court effectively takes the gun issue out of the fall campaign. Republicans will now have a very hard time arguing that if you elect Democrats they will take away your guns.

Via Glenn Reynolds, who added that “Obama’s record of strong support for sweeping gun control would hurt him a lot more in a climate where gun owners felt more threatened.”
While McCain might not be able to argue that “if you elect Democrats they will take away your guns,” everyone knows this was a 5-4 decision, and that three of the justices are due for replacement. What that means is that whoever is elected will be tasked with creating the new, post-Heller majority. Thus, while the gun issue might not be a direct campaign issue, it’s a heck of an indirect campaign issue. Most likely the issue will be subsumed in a discussion of judicial philosophy, but those who care about the Second Amendment won’t forget what’s at stake.