The present countries that are part of Latin America were formerly under the dominion of the European powers of Great Britain, Spain, Portugal, and France. However, as the United States began to increase its might, it made it known to the European powers, through its Monroe doctrine -- that it would not broker European meddling in the affairs of Latin America, for Latin America to the United States, was considered to be solely in the domain of the United States. To a very large extent, the United States got exactly what it wanted, for all the Latin American countries, ultimately became sovereign essentially during the 19th Century, and therefore as independent nations were no longer beholden to European powers.
However, though these Latin American countries were successful in throwing off the chains of European oppression, they were to a very large extent, susceptible to a new master, which not too surprisingly, was and is the United States of America. The United States, while it has claimed some foreign territories as its own, such as Puerto Rico, and the United States Virgin islands; has nevertheless, in most instances, preferred to be involved with Latin American countries in a way that is not so explicit, yet, still has massive repercussions for those countries, involved.
To wit, these Latin American countries have both natural resources as well as industries that those that are the ostensible leaders or power brokers of those nations, wish to see be successful and productive; of which, the United States, has the expertise to help provide and to accelerate that success; but often the fruits of that success are structured in a manner in which specifically the applicable United States institutions benefit, as well as the elite few of those Latin American countries -- whereas the mass of the population, does not. When the best expertise and most modern equipment to extract natural resources of a given Latin American country is readily available from the United States, than such when provided to those Latin American countries, invariably comes with strings and contracts that are attached, that are usually quite favorable to those American consortiums that provide that equipment for the extraction of those natural resources. Further to the point, countries that have natural resources as well as other practical assets are most definitely in need of capital in order to build both the infrastructure as well as to create the necessary means to export goods and other materials, in which that capital often comes from western nations, of which, the terms and conditions of those contractual obligations are structured in a manner in which those Latin American countries which become indebted, typically are not ever able to develop the necessary means to successfully pay off that debt, and further seemingly inevitably negotiate from a position of weakness, against those that have all or most of the cards.
While the governments of the Latin American countries are independent by Constitutional law, most of them are in one way or another materially and structurally indebted to the United States of America, and further, those that are Latin America's industry and political leaders are usually quite content to work closely with the United States of America, because it is personally beneficial for them to do so. The United States of America is an empire, and as in most empires, those countries that are in close proximity to the United States of America, are also those countries that most often dance to the tune that the United States of America desires to play.