Out of all four listed Korea was the best bet.
South Korea was really invaded had a climate more suited to conventional war than Vietnam did and had a population much more suited to modernization and a working democratic government than those poor Islamic crapholes did.
Also the UN supported it.
But in the end after years of stalemate Americans will always be asking why those we are helping are not fighting their own wars.
“...But, similar to delete the aftermath of the collapse of South Vietnam, Americans today do not want a ground war to fight the War on Terror....”
When the “other guy” is completely ready, willing, and increasingly able to bring “the war on terror” to your doorstep - or to your high rise buildings in NYC, schools and stadiums in Anytown USA, etc., - “what Americans do not want” quickly becomes irrelevant.