The way I see it, North Korea could have two motives.
Motive 1: It really is just launching a satellite. Its purpose, however, remains unclear. It could potentially be a spy satellite. Who knows? The uncertainty is enough to intercept it anyways.
Motive 2: North Korea actually wants someone, likely the U.S., to intercept the supposed satellite/missile. Why would they want this? Because of what I already mentioned: they're tired of being ignored by the global community. They want some attention. And you and I both know that when someone really wants attention, they'll do pretty much anything to get it.
Now it won't be that hard for intelligence agencies to find out whether it's a satellite or missile, right? So if it's a satellite, no harm done I suppose, and no baseless war (but again back to the possibility of a spy satellite...). If however, it is a missile, something obviously has to be done. But will it? North Korea is the thorn in the world's side (along with Iran, Palestine, Mexico, France...), so I say that something should be done, and if North Korea goes to war with the United States, we blast them to smithereens. Kim Jong-il would be an idiot to attack us. Liberals, on the other hand, love to wait until not even the last minute, but after the event has taken place, to do something about it (even then, they try to do the least possible). And then they blame the current administration (but only if it's Republican) for not doing enough in time (which means that if North Korea decides to bomb our cities, the great peacemaker Obama will be off the hook, and I bet Bush will be somehow blamed - it's always the same old song and dance).
Assume hell has frozen over and Obama decides to do something in America's best interest and actually decides to put an end to North Korea's antics. North Korea assured that it will react with the "most powerful military means." Does that mean North Korea is now threatening to use a nuclear bomb against anyone who intercepts its "peaceful satellite?"
I feel like this is the Korean Missile Crisis, but things won't turn out quite so well.