Well, it's a complicated subject because I believe there are multiple threats from multiple sources, any number of which could mean some real problems for us.
Iran has to be up there toward the top, though. It doesn't have to be that way, but through Barry's absolutely stupid management of the Iranian effort toward obtainment of nukes, they're a lot closer to their goal than is comfortable. Don't believe me? Ask the Israelis.
If push comes to shove and things become a little more overt between Israel and Iran vis a vis Iran's nuke sites that have been mysteriously blown up, it's going to put a severe damper on the world's supply of oil. The Strait of Hormuz becomes a battleground and the cost of crude will immediately spike to unheard-of levels. That kind of shit gets Americans in an uproar, most ricky-tick.
North Korea is essentially ostracized and isolated. I don't see a huge problem with that country, unless they decide to go really rogue and launch something at Japan.
Perhaps more than any of these two countries, I fear the USA for posing the greatest threat to the USA. The entitlement mentality (again, Adam Carolla's rant was stellar on this issue), and Congress' own refusal to fix issues out of fear for their jobs (professional politicians were not on the minds of the Founding Fathers, it seems to me) all spell an encroachment upon our culture and way of life that could transcend anything that Iran or the Norks could toss at us.
It ain't looking real good right now, even though unemployment has dropped to 8.6% (not factoring in those who have given up in finding work, of course).
