Here's why I think nothing happened today
First, some facts
-America can't really afford another massive war
-China doesn't want to fight the US, and vice-versa
-The North wants to save face
So............
What if the US said to Korea, "Don't attack when the South hold their drills. We have a better deal for you. As long as you don't start the [prospective] war, we won't enter it."
But the catch...
They add "You have to save us some face though by allowing the UN inspectors in and agreeing to our offshore uranium processing demands."
The North thinks about it for a bit and says, "Okay."
The US call the Chinese and the Russians and tell them that the North will not attack South but it is likely that the South will eventually find a way to punish the North militarily - thus starting the war.
The Russians and Chinese are happy with this arrangement, as it doesn't involve WW3, just a good old one-on-one Korean fistycuff.
The winner takes all.
If North Korea win, it becomes China's problem to contain them if need be.
If South Korea win, it's with very heavy losses and renewed US/Chinese influence on the peninsula.
-Never doubt that a small group of thoughtful, committed people can change the world. Indeed, it is the only thing that ever has