What's Really America's Biggest Adversary Today?

Is it Iran? Pakistan? ... Corn syrup?

Nicholas Burns -- a former under secretary of state for political affairs, U.S. ambassador to NATO and Greece, State Department spokesman, and special assistant to President Clinton -- is prone to skillfully parsed statements. When The Atlantic's Jeffrey Goldberg asked him at the Aspen Ideas Festival this week what the United States' number-one adversary in the world is, Burns's reply: "Iran."

Goldberg: "No doubt in your mind?"

Burns: "None."

Of course, given its nuclear and ballistic-missile programs, its history of support for terrorist operations, and its other qualifications for the number-one slot, not to say President Obama's own assessment of the threat it poses, Iran is not a particularly surprising answer -- as might be, say, Russia.

But is Iran really a bigger threat than, well, Pakistan?

Richard Haass, president of the Council on Foreign Relations, framed the picture like this: Iran is an imperial power that wants to spread it's influence in the Middle East -- and one of the options they're pursuing to this end is a nuclear weapon. Pakistan is not an imperial power. The threat it poses isn't from a strength -- or a new strength it's trying to develop -- but a weakness: the prospect of its implosion. Pakistan has upward of 100 nuclear weapons; it's a sanctuary for terrorist organizations now; and it's already been the base of operations for the biggest nuclear smuggling network ever -- "the Walmart of nuclear trade."

Whether or not Pakistan is itself tipping toward failure, the situation in the country is, as Burns pointed out, dramatically worse than it was three or four years ago, and relations between Islamabad and Washington have bottomed out, weakening American leverage against the dangers Pakistan represents. There is, in fact, "no trust," since Obama ("rightly," Burns was careful to include) took out bin Laden in 2011.

Also in Aspen today, General Stanley McChrystal, former commander of U.S. and International forces in Afghanistan, had a different optic on the question altogether. The biggest threat to the United States isn't in Iran or Pakistan -- these, we can ultimately deal with: "We have the technology and forces to do that." The greatest threat is "in our schools," he said, noting the U.S.'s low high-school graduation rates, and the physical problem of obesity. "Thirty-three percent of the nation is ineligible to serve in the military," he said. " It's a national security issue."