The importance of the US military presence in Korea has nothing to do with occupation and domination, nor is the true power of the US presence in any way proportional to the exact number of troops (around 37,000). Although perhaps true that South Korea has sufficient resources to beat back a North Korea attack and invasion (that's exact how the whole bloody thing began a half century ago - blatant communist agression) losses would be very heavy.

The huge technological advantage (which Pfaff doesn't even bother to mention) of the American forces, especially in air power, would obliterate an invading North Korean force, leaving scattered ground forces for the South Korean and American ground troops to clean up. Sure there would be casualties, but a hell of a lot less than if the Amercans weren't there.