Two wars at once?

[Skandranon]

Note that in the event of a war with North Korea, the USN can rely on support from the Japanese MSDF, currently the most powerful navy in the Asian area. Four AEGIS-equipped missile destroyers as well as a large number of other guided missile destroyers, as well as an amphibious assault ship and a number of diesel submarines, if necessary. I don't see any circumstances where North Korea starts something and the Japanese don't jump in - North Korea likes firing missiles over their country, after all, and is more of a threat to them than to the US. With MSDF support, the USN needs only to expedite training and workup schedules for two more carriers (the US has 14, IIRC - 7 in and 7 out of overhaul is pushing it, but not impossible if really necessary) and send them with an understrength battlegroup to Japan. As for actually invading North Korea with ground forces, I don't think the US will do that, but rather will diplomatically point out to China that instability in North Korea is substantially less good for them than it is for America, whereupon the PLA will do the job.