So, let's flip the question around. Why is this even worth asking? I mean, nobody asks why Stalin propped up dictators — it's entirely within his character.

The answer, of course, is because the US rhetoric, especially that of the Cold War, was about a clash of ideologies, about the "free world" versus an "enslaved world," about the US being the country that opposes dictatorships in favor of democracy, and so on and so on.

And so we are faced with an answer that is as self-evident as it is banal, yet is very shocking to people who have arrived at it for the first time: the political rhetoric of the US during the Cold War was very much out of step with its actual practices.

This is hardly limited to the Cold War, to be sure: the US has a far worse record on things like "freedom" and "democracy" and "human rights" than it likes to say it does. And what's odd is, as an American, you are told both of these contradictory narratives, but rarely do they have to interact with each other directly. So in school we learn that the United States is a country defined by freedom, democracy, suffrage, human rights, equal treatment before the law, and so on. And we also learn about slavery, violent treatment of the Native Americans, the Civil Rights Movement, the denial of the vote to huge groups of people, and US injustices in Latin America, Asia, what have you.

And yet, despite the latter issues, the former vision remains intact. Occasionally, but rarely, it gets a caveat: we strive towards freedom (may not always be doing it). Or that we did things out of step with these values in the past. All of this is still disingenuous, if you are being serious about US policy both domestically and abroad, historically and in the present day.

(I am reminded of an instance in which a well-meaning HR employee at an institution I worked at in the past sent several e-mails imploring us to go to a Patriots' Day BBQ. All of that is fine as far as I am concerned — except she kept saying it was to celebrate the Founding Fathers, "who fought for the freedom of all Americans." And this is simply not a true reflection of what the Founding Fathers were doing! Such is the disjuncture: I am 100% positive that this well-meaning person knew about the history of slavery and that both Washington and Jefferson were slave-owners, and that the American democracy was until the 20th century in practice limited almost exclusively to white males, and yet that part of understanding was kept well and separate from the jingoistic nationalistic view of American patriotism that they were trying to celebrate. And it's not like I disagree with the ultimate sentiment: freedom is a good thing! But to conflate values with historical realities easily leads to such category errors.)

But I digress at length. Why did the US prop up dictators? One can give a simple answer that applies to many time periods, not simply the Cold War: because it saw doing so as being in its political and economic interests. Boring answer. Perhaps tautologically so. But a true answer nonetheless.

Again, the only part of that answer that is interesting is that it contradicts a narrative about American priorities, one that either says or implies that idealistic notions of freedom and democracy are held as values higher than other short-term political or economic needs. And that has frequently been plainly false.

In terms of the actual Cold War, specifically: the US saw the world as a global playing board for a high-stakes game of political power. It interpreted, sometimes correctly but often not, anything that looked like socialism or Communism as being a ploy by the Soviet Union to gain additional power. And so within said nations they sponsored and supported groups that opposed Soviet power, however that frequently meant military juntas and harsh anti-Communist dictators, especially in the developing world. The US took the examples of China and Cuba especially hard, seeing them as foretelling a Communist conspiracy that would surround the United States, and instead dedicated themselves, again and again, to trying to "contain" the Communist menace.

One can ask: could the US have prosecuted the Cold War differently? Could it have worked to support moderate voices? In fact this is what it did, very actively, in many countries, notably in Western Europe, where the CIA propped up not right-wing radicals so much as moderate, anti-Communist liberal voices. But in much of the world, rightly or wrongly, it did not see this as an option. Perhaps this is because it at times had a lack of faith in developing peoples to have moderate opinions (democracy is a hard institution to start from scratch, and can easily lead to ignorant populism that can swing into political extremism; this is not merely the case in the developing world, alas). Perhaps this was also at times simply a lack of options in a world where the US rarely made the political centers of power from scratch, but rather had to deal with what players were already on the board. (In looking closely at US interactions with South Vietnam, for example, one easily sees that they were hardly infatuated with their allies — Kennedy and Johnson felt great frustration and anger at the cruelty and ineptness of the South Vietnamese government, but what was the alternative? The answer, for Kennedy, ended up being giving some sanction to a military coup — and that arguably made the problem even worse.)

The big danger in the above is that it glosses over "the United States" as if it were a monolithic, transhistorical entity. In reality the different US administrations had different attitudes on this point. Some were explicitly realpolitik in their foreign policy, seeing things like "moral values" as being at best a card to be played in the "great game," and not actually a motivating force. So Kissinger is especially famous for being overt about this, but one can find similar views as this in many figures, including Roosevelt. In other administrations, some of this noxious "support" was given with a generous holding of the nose, and in some, strong pressure was put on US allies to lessen their harm or even reform. So one should not fall into the trap as seeing this as one simple equation: US foreign policy evolved over time, with different administrations, different perceptions of the "threat," and a different world context.

Similarly it is easy to misunderstand or misjudge the USSR, which sometimes did try to expand, and sometimes did not. Some of the "revolutions" abroad were sponsored by existing Communist states, and some of them were, it seems, relatively "innocent" attempts at economic justice. It should be noted that these kinds of distinctions are difficult to make even in retrospect, and were certainly hard at the time. None of the above should be construed as implying the US should have easily been able to take a different path — even in retrospect it is not clear what the "best" alternatives might have been in many cases, and of course we cannot re-run history as if it were a simulation tape.

If anything, my main point is: examine why you find such things surprising, and, for the love of all that is historical, don't adopt uncritical stances towards any nation. The United States is a country in the real world. It has a very messy history and a very messy present. As do all "real" countries. The cognitive error here is expecting otherwise, and buying into the myths we all-too-readily tell about ourselves and our history.