THe OP calls the US pyschotic and you want to avoid flamebait?
Yah, but put it this way.
Mention the word 'socialism' to the average US citizen, and watch their reaction.
Most Americans I have met react viscerally to the word socialism. As I understand it there is a reason for the American (mis-)use of the word liberal to mean left-wing, which is that the word socialist is completely off-limits, and a 'socialist' is beyond the political pale.
It is therefore a valid question, if inflamatorily phrased.
I would also like to amend nbcman's list. I'm not sure Cuba belongs on the list of hard-line states still covered.
The main point of issue is, does the left-wing split, between those who are 'socialists' and prepared to deal with the USA, and "the rest", thus resulting in a world more friendly to the USA - call this option 1.
OR, in option 2, does this American "weakness" encourage the spread of communism under a cover of milder 'socialism'. For example, protests take place against a Central American dictator. Since Communist influence is not apparent, and he is a rather unsavoury character, the USA turns a blind eye. The new progressive government, once it cements power, purges itself of the milder elements and turns to Moscow for arms and support.
Now, I'm no American fanboy, and there are limits to the cunning even of a regime which is pathological in it's deceit. However there is a point to be made that America was the leader of a vital struggle against a very serious enemy. It is possible that a greater toleration of what have been called "fellow travellers" would have weakened the American bloc. In other words the American intolerance to anything smacking of the left of centre may be part of the price the world paid for NATO winning the Cold War without it turning hot.