BUSAN, SOUTH KOREA – With the huge USS George Washington aircraft carrier getting ready to steam out of the South Korean port city of Busan tomorrow, heading up the joint US-South Korean war games, North Korea is ratcheting up its war-like rhetoric.

North Korean officials are threatening a “sacred war” using the country’s “nuclear deterrence” if the “reckless” exercises go forward.

Respected Korea expert Peter Beck, currently in Seoul, called this more “sabre rattling” by Pyongyang.

That’s a good thing, because the maneuvers are going forward. They involve 20 US and South Korean ships, 200 aircraft, and 8,000 service members, and will last four days.

The wild card in all this is that the North Korean regime is in apparent turmoil with a succession drama said to be playing out involving current leader Kim Jong-il and his third son Kim Jong-un.

“Something is going on up there,” Beck added, “It looks like they’re rallying around the Kim family to make sure the succession goes smoothly.”

That could explain the rhetoric, recent reported executions of those not faithful to the regime, even the sinking of the South Korean warship the Cheonan in March, which triggered these exercises.

“If only half of what we’re hearing from the North is true,” Beck told us, “ there are problems.”

Which means that something unexpected happening during the exercise is not ruled out by the military.

Which makes these exercises, which have been described here as one part signal to North Korea to lay off, and the other part signal to South Korea that the US is behind them, all the more important to those involved.