What are some advantages of isolationism

1. You don't get tangled up in some bloody war. 
2. You don't have to spend a lot of money on other countries problems. 
3. As a government you can focus more on the needs of your countrymen. 
4. You don't have to keep a large military on hair trigger notice. 
5. You're not likely to make enemies out of some random country halfway around the world. 

nonparticipation in any alliances, economic commitments or foreign trade, to avoid diplomacy entanglements with foreign countries

Some causes of the Korean war were
-The Cold War
-A communist China
-US fears of Communist expansion in Asia
-Korea's 38th parallel division
- North Korea's communist gov't. 
- The UN support of S. Korea