You think US involvement began or was only a thing of last dictatorship? I once read a book that explained meticously the work done by the german embassy in Argentina during the WWII. They competed with the US embassy and with the english embassy. Argentina remained neutral, but the work done by these embassies were huge!
After the war ended, in 1946, Peron won an election, competing with Braden, the US ambassador. Go figure the work the embassy did to put someone at the same height than Peron. The slogan in that election was "Braden o Peron".
So lets think, if the candidate of the US embassy lost against Peron, that means that yes they respected the results but also that they would destiny all their resources to oppose to everything Peron would do. So they did, when the militars bombed Plaza de mayo in 1955 and afterwards overthrew Peron, the US were on their side.
Embassies do a lot to make things happen. German embassy during WW2 was one of the causes of Argentina neutrality.
My point is that if they weren’t directly supported by the US in the previous dictatorships, that does not mean that they didn’t have support at all. They had the main super power (military, economically, etc) on their side. If things get difficult, as they finally did, they, the militars, knew they could count with them. Every dictatorship and even democratic governments (who won without letting Peron to postulate-how absurd is that) had the explicit support from the US.
The democratic and “stable” governments after Peron was overthrew were 100% under control of the militars, so there wasn’t really a possibility of a democracy. The options were or the militars, or some kind of fake elections between Conservatives and UCR. Again: they did not allow Peron or any form of Peronismo to participate in those elections. That for 20 years. IMO that was the cause of the guerrilla. Of the Resistencia Peronista. Of the bloodiest dictatorship that followed.
Of course the militars weren’t born in the US, they were 100% argentines, born and raised. As the half of the country that was anti peronista as well (well, in fact, less than the half, Peron won in 1973 with 62%). But it was like we have it today, half and half. I don’t think is Argentinas fault for having two world views incompatibles. It happens everywhere, almost. It wasn’t the US entire fault of course. Corruption is 100% Argentine.
But the geopolitics, what the US wanted for the region, as well as we have it today, working with narcos, insecurity, terrorism, etc , played a very important roll. They always had the power and the control of the situation, and if it goes out of it, then they always could have done what they did. The result of the fight between the two halves, peronistas & anti peronistas, was in fact a direct product of a US government implanted by force. The destiny of Argentine dispute was to be solved by forces from outside. Geopolitics decided the battle, if we can call it battle cause it was an entire army plenty of resources, trained in the School of the Americas (how to torture, to disappear, etc) with intelligence, tanks, planes, etc, versus a 5 thousands young soldiers armed with pistols supported by Cuba.
As we say in Spanish, cuando las papas queman… so that’s the evidence that the scenario before the last dictatorship was under control by the US, only that they didn’t need too much force, it wasn’t so explicit.