JFK (circa 1961):
1) Confiding to his special assistant, historian Arthur Schlesinger, Jr:
..."They [Pentagon] want a force of American troops...They say it's necessary....Then we will be told we have to send in more troops. It's like taking a drink. The effect wears off and you have to have another....The war in Vietnam could be won only so long as it was their war. If it were ever converted into a white man's war, we would lose as the French had lost a decade earlier"...
2) At the University of Washington, Seatle:
..."We must face the fact that the United States is neither omnipotent or omniscient...that we are only 6% of the world's population, that we cannot impose our will upon the other 94%, that we cannot fight every wrong or reverse each adversity, and that therefore there cannot be an American solution to every world problem"...
Source: Lessons in Disaster, Gordon Goldstein, pp. 65-66
LBJ later reportedly said "I will not be the first American president to lose a war"....and then he had to send in more and more troops to protect those who had gone in before.
Just as JFK predicted: - It's like taking a drink. Except it's not Pepsi but that of JIm Roger's Kool-Aid brew.
JFK was a student of history. He wrote "Why England Slept" in his hospital bed and won a Pulitzer. While many say Arthur Schlesinger Jr. was the ghost writer, but the more salient point was JFK thought like a historian even if he had not written that book.
How many contemporary US leaders know history? Did Bush know the Brits, masters of empire management, got their royal behinds kicked in Mesopotamia, the ancient name of Iraq? Did he and his Yale/Princeton/West Point educated subordinates know Afghanistan was also known to historians as the "graveyard of empires"?
If they did, what made them think it would be "different this time"?