You said 1950 1980.

If you read into the problems of these countries they had problems starting around the 1930s. (Well before that but the current type of corruption that hasn’t changed) 20 years prior to the “American problem”.

They continue to have problems to this day. 30 years after the American problem you described.

They hold elections every 4 or 5 years depending...Most if them can’t run consecutively or serve more then 1 term as their president.

The #1 problem of all these countries is......Ding ding ding...... Drugs and drug money. It’s the epitome of their problem and will continue to be biggest threat to a stabilized region in South America.

The “millions” of dollars American companies have spent over that 70 year window, for a project here and a project there.

They estimated trillions of dollars that have passed through their country has ultimately caused the biggest issues they have. At this point they can’t get a grip on it without a civil war probably.