We're not going to see Asian nations uniting against Japan. The US is unwilling to see Japan undefeated and will clobber the PLAN/allies if it feels the Japanese navy is going to be desroyed. This is because Japan is America,s main strategic partner in Asia. OF course, the US wouldn't want to see South Korea lose either because South Korea is another American ally, so there would be tremendous US pressure to end the war. The US wouldn't support either side because it would lose an ally, and it would look very bad is Japan/rest of Asia, depending on what side they picked.