wouldn't be the first time they've bluffed
Well, there was a ~4.1 earthquake type rumble (on some sort of altered frequancy from a normal earthquake) that epicentered right about where they've been doing that shit.
As for the more policital end of things, I don't see why any nation hasn't taken any effective (I do not see sanctions as effective. At all.) actions reguarding North Korea yet. It seems like... Japan, Russia, South Korea, might be... slightly concerned?
Some folks say "WHY THIS WAR AND NOT IRAQ?!" Well, it's quite simple. Iraq doesn't have any nukes. Plus, if we're planning on fighting this in the method we have fought Iraq, I don't support it, at all. Bomb them, k, done. Foot invasion, uh, no. While we're at it, we can drop a few on the nuclear development sites in Iran, since there's no real reason for them to be there.