Everyone needs to understand, war with North Korea is strategically impossible without being willing to accept tremendous losses for our allies (South Korea and Japan) and probably resorting to a strategic nuclear engagement. There are several reasons that each of these concepts holds.
First, understand that North Korea probably has roughly 5 ready to go uranium gun-style nuclear weapons. They're previous test is believed to be a plutonium implosion-style device that either failed, was extremely low yield, or was an attempt to achieve boosting (enhancing a standard 15-20 kt device to 250+ kt also granting an arbitrary yield with minimal weapons-grade material). Either way, we know they have sufficient weapons-grade uranium and plutonium to have built at least 10 15kt devices. Building a gun-style nuke is within the means of a high school science class, given the materials, whereas the plutonium device requires far more precision, development, and the proper equipment.
Second, even without their nuclear capacity, (let's assume we destroyed it with a preemptive nuclear strike, or that our anti-missile batteries in S.Korea and off the coast destroyed them) N. Korea is still left with hundreds of thousands of ready-to-launch mortars aimed at S. Korea. Furthermore, the DPRK is known to have chemical agents at their disposal that could easily be mounted on their rather large and reliable medium range missile arsenal. The threat of a WMD attack against Japan is severe, in any scenario of military conflict against N. Korea.
Lastly, any air assault against N. Korea would bring about a full response against S. Korea. We're talking about tens of thousands of American troops (our 'tripwire') probably being overrun by half a million ready-to-die N. Korean soldiers (again, soldiers. not angry civilians wrapped in blankets with AK-47s).
While the United States could "win" a conflict against N. Korea, the losses could be far greater than those incurred in Vietnam, and there are almost no plausible scenarios in which nuclear weapons wouldn't be used by either side. Politically, it would end any Presidency and destroy any political party's hopes to govern for the next 20 years; therefore, it's very difficult to see any administration advocating an attack against North Korea. And to that end, it makes perfect sense why the North Koreans developed nuclear weapons in the first place. From the moment they developed their first nuclear warhead they were assured to never be bombed, and to always be relevant on the world stage. Now, if we want them to give us their nuclear material (yea right), then they're going to want to be paid -- billions.
IMO, the best strategy to use against N. Korea is to impose 100% international sanctions, including all forms food and medical supplies, and simply ignore them. Have high flying aircraft carriers jam all transmissions over their country with Flavor/Rock of Love, and other pop culture programs. Beyond that, starvation would quickly force them to into a regime change.
Uranium for food sounds good to me.