"MacArthur should have been fired months before, when after the Inchon landing he failed to cut off the North Korean army from fleeing north. Instead of driving across the penninsula, MacArthur wasted weeks taking Seoul. "
Let's not forget that one argument against the Inchon landing was that troops had to be pulled out of the Pusan Perimeter. We were still desperately undermanned and undertrained, thanks to the "cuts to the bone" of the Truman administration. After that, there was fierce resistance in Seoul. The fighting was house-to-house, and slow. Gunfire could still be heard in the background when Mac flew to Seoul to "officially" return the city to Rhee.
I very much doubt that logistics could have been arranged to allow us to fight all the way across the penninsula at that time. But for Mac's genius in pulling off the Inchon landing **at all** when nobody thought he could, that war might have taken 5 years just to fight northward from Pusan to the 38th parallel.
"Then, he further screwed up by disobeying orders and advancing all the way to the Yalu River. "
I always have to think about the possibility that someone has information that I don't, but my take on that is, I don't think Truman ever ordered him directly and clearly not to advance to the Yalu. If the Chinese had *not* come into the war, Truman would have endorsed Mac's actions.
That said, Mac should have known that the Chinese were telling us they would come into the war if we advanced to the Yalu. The signs were clear. I blame Willoughby, Mac's intel officer and one of the Bataan Gang to whom Mac was unfailingly loyal.
Scuttlebut is that it was Willoughby who kept intel from getting to Mac telling him that the Korean War was imminent, and that the entry of the Chinese was a virtual certainty. Even so, Willoughby was of course Mac's subordinate, so the buck stops there.
My opinion is that the main problem was that a mediocrity like Truman simply could not abide a great genius like MacArthur.
MacArthur should have bypassed Seoul to get across the penninsula. If he had the wherewithal for street fighting in Seoul then he could have gotten across the pennsinsula in time to cut off the North Koreans.
Don't overstimate MacArthur. He's the "genius" whose planes were destroyed on the ground the day AFTER the attack on Pearl Harbor. Also, he screwed up the retreat to Bataan so badly that he left behind in Manila the year's supply of food his troops were supposed to take with them.