Being stationed in Korea is not a bad gig. You make quite a bit of money there and it's a nice place to live. It's not different than being stationed in Japan and saying we should leave and let the Japanese defend themselves. Should we? No. Yeah, South Korea may have a huge army, but take a look at how many of those are reserves. Plus, add in the fact that you have Yakota, Iwakuni, Kadena, Futenma, and Anderson all within arms reach. And those are just the biggest bases, I'm not even mentioning places like Camp Foster, Camp Lester, Camp Hansen, Camp Kinser, Misawa AB, NAF Atsugi, and Camp Zama. The sheer amount of American Military Iron in the Pacific region is rediculous. Not to mention the amount of C-5's and C-17's loaded with equipment and personnel that would flock over here if anything kicked off.
We'd wreck their shit.