The US, China and Russia were busy trying to extend their influence into a new world. Dean Acheson had left Korea out of a declaration of America's sphere of influence, leaving the impression South Korea was in effect abandoned. (Much like April Glaspie did with Saddam re Kuwait.)

North Korea was a communist satellite, and their army had been trained and armed by China and Russia. However, the country was run by a native Korean. The Chinese and Russians who have talked about the start of that war say that in the midst of all the saber-rattling Kim Il-Sung built up his forces on the border.

And then he took it upon himself to invade, and did so without the permission of either of his major power sponsors. At that point the Soviet Union and China were presented with a 'fait accompli'. They provided arms and air support, but did not provide ground troops until the UN reached the Yalu River.

With a UN occupation of the entire peninsula becoming a real possibility the Chinese came over the border. But only then.

And both sides came to a standstill around the original 38th parallel.

Do you think that neither side could advance farther? That the UN (US) couldn't have fought north, or that the Chinese, with the rather easier logistical problems, the unlimited manpower and the Soviet supplies couldn't have gone on down the peninsula?

If you think about it I believe you'll realize it is no coincidence that the reasons for the original division of the peninsula were the reasons for the line at the time of the cease-fire. And understand how odius it would be for them to have us on their borders, and for us to have them that close to Japan, which was at that time a source of cheap labor for US manufacturers.

Arf