Poland I remember but please remind me about South Korea.
http://en.wikipedia.org/wiki/Cheonan
The NORKS always challenge the new president with a crisis to see what they can get away with. When Nixon was elected they shot a couple of US Army officers over the DMZ. Nixon immediately ordered up a couple of carrier task groups and said he’d blast them back to the stone age. The NORKS hastily backed down and provided video of them shooting the marksmen who allegedly did the killing, allegedly without orders. No more problems for Nixon. But Obama failed the test. The NORKS sank the Choenan. SK begged Obama to respond with force. They even released data on the attack to shame him into moving. He sent a sternly worded diplomatic note. We’ve had nothing but problems with them since.
If I were SK I’d be developing my own nuclear umbrella. (Oh, Obama withdrew all sub launched nukes. The Japanese learned of this crazy move and protested. Allegedly Obama countermanded his order.)