This, along with Pyongyang's plan to fire off a long-range missile, is a problem for President Obama (tip to Instapundit):
Any hostile actions by the North's submarines would be a political bruise for President Obama, whose administration struck an apparent deal with the North under which the U.S. would send food assistance in return for Pyongyang halting nuclear testing. ...
"This is precisely why Obama made the deal: To avoid these kinds of provocations," Cha says, adding Obama "must be steamed."
Well, the problem for Obama is that he probably didn't make it clear--as he did to Putin through Medvedev--that in exchange for some "space" where the Korean peninsula remains quiet through November, President Obama will show more "flexibility" toward North Korea.
North Korean internal politics may require the moves regardless of their hopes for goodies from us. I can only assume that the North Koreans assume no outrage is too much for an American president who needs space before his reelection bid.
UPDATE: Thanks to Instapundit for the link.