But certainly, half the idea was to force military actions that would divide political support here, then play them up to the useful idiot crowd. That part you can indeed say "worked". Then again, it didn't exactly elect George McGovern. Notice also that it was hardly our domestic useful idiots who had lost their security. In Algeria, the last to give up were the Harkis, and in South Vietnam, the last to give up were the ARVN.
Moral - let's not call too loud on "inevitability" to cloak our own failings.
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At the end there were two North Vietnamese thrusts, one from the NE with a very concentrated formation of communist troops, and a thrust from the north with Soviet armor. About five napalm bombs in the NE would have destroyed about 1/3 of the northern army. However, by that time Jane Fonda, Ted Kennedy, Berkeley radicals, Joan Baez, leftist journalists, and followers of George McGovern were were in control of our military policy.