Not everything needs to be answered with invasion. Iraq was a hopeless situation to deal with. Saddam played too many games.
Iran and North Korea are different situations. With NK I fully believe the Chinese will deal with them and put the smack down on Kim. I don't think China wants nukes in their backyard held by a madman.
I think pressure in the Middle East will escalate, whether it leads to war with Iran I have no clue, but I think some of those countries might start thinking twice.
But hey, I'm just a silly American that wants to control the world, so what do I know.