Obama should tell Japan to "at least threaten to go nuclear unless China reins in North Korea"

Yes he is. He called mancow the other day and told him waterboarding still wasn't torture, so there.

Diplomacy has brought China into the issue.
There's alot of territory between diplomacy and a nuclear threat. Some have worked really well, even against such pathological government leaders as those of N. Korea.

There is a little difference this time through. I say difference, because...

1. China is angry at N. Korea for doing this, and for taking these aggressive actions. This is a lot different than times before when China would cover for, and apologize for N. Korea.

2. Russie is also angry at N. Korea for doing this. Again, this is the difference from other times. Russia would also cover for N. Korea in the past, harkening back to the times of Stalin.

Escalation, is NOT what the world needs in the least. Japan, is averse to nuclear weapons for reasons that are quite justified.

North Korea is a sabre rattling nation, always have been. It's not so much that they have nukes, it's that they're loose and fast with selling that sort of stuff off to countries that we really don't want to have them, or individuals we don't want to have them. And even if they don't sell a device, some unsavory individuals could get nuclear material for a dirty bomb, which could be pretty bad. Which is why...

We are looking at running a blockade against N. Korea to intercept their shipping out of their country to ensure nuclear materials don't fall into the wrong hands. Sure, they said they'd shoot at us if we did that, but N. Korea cannot afford to do such a thing, mostly because they will not have a single friend left in the world if they did do that. China, Russia, and other countries would be behind our actions if they did shoot at our naval vessels.

N. Korea has a large standing army, but, they are poorly equipped, and their supplies are in short order. If they had to fight battles, they would lose, greatly.

The Iranian kook has no real power. The power in Iran resides firmly in the hands of the Ayatollah, the spiritual leader. The President of Iran has no power to really do anything. He is nothing more than a front man for the real power. Also, in order to make the hardliners feel comfortable, the President of Iran needs to say these crazy looney things. Iran would never attack Israel, for the mere fact that Israel would wipe them off the face of the Earth in short order if that actually happened, with our full tacit support. And Israel also has nuclear weapons, ready to roll.

Also, the thing about Iran is that they have a young population, that is more likely to agree with the US than their own leadership. We have been trying to make inroads for years on end to try and get the people to have a larger voice, to start taking back their country. Iran is run by ideologues, but the population, as a whole, are not. That's the main problem with N. Korea is that the population is insulated from outside sources of any and all information, and the entire populace is brainwashed to the wishes of the dear leader. Iran is much different, and not in the same place as N. Korea.

Kim Jong Il LOVES attention as well.