Julian Zelizer suggests Obama’s advantage on foreign policy may not be as significant as it seems:

The third vulnerability is the fact that foreign policy has been notoriously messy in the post-Cold War world. The kind of clarity that foreign policy had during the Cold War, with a clear enemy and clear areas of competition, has been gone since the 1980s.

That has been replaced by a world of foreign policy defined by amorphous terrorist networks, rogue states whose loyalties are constantly shifting and ethnic warfare in which it is difficult to distinguish the good from the bad. President Bill Clinton and Vice President Al Gore learned how difficult it was to develop political capital in this world of foreign policy. Despite a significant victory in Kosovo, where American air power helped bring down Serbia’s Slobodan Milosevic, foreign policy success did little for Al Gore when he ran against Bush in 2000.

Unless a majority of voters believes that national security is at stake, emphasizing an administration’s foreign policy record is often not very politically useful. Kosovo was mostly irrelevant as an issue in the 2000 election. I should add that Milosevic’s later fall from power was only very indirectly related to the war, and the war didn’t cause Milosevic’s fall. The only measurable political effect of the Kosovo war may have been the new Republican tilt of some Serbian-American voters, who were understandably appalled that their government had illegally attacked Serbia. In addition to being unconnected to any American interest, Kosovo was not an especially popular campaign, so there really wasn’t much political benefit that Clinton or Gore could get out of it. It was also not that much of a liability for Gore. There were no U.S. casualties, Bush had supported the war all along, and the public’s attention was focused almost entirely on domestic concerns. In the same way, “success” in Libya isn’t going to translate into any advantage for Obama, but Romney won’t be able to make an issue out it.

In order for a foreign policy “success” to lend the incumbent party any sort of electoral boost, the success has to be perceived as such and widely accepted as relevant to American security. This is why the Obama campaign makes a point of drawing so much attention to the death of Bin Laden. It doesn’t matter to most voters that the death is mostly symbolic or that its significance has been wildly exaggerated. After eleven years of constant warfare that haven’t yielded all that much in terms of improved U.S. security, it one of the few events that means anything to most Americans.