The thing about European powers back in the time of their pinnacle of such power, is that the major players in Europe made it their point, to rule over other foreign lands in a manner in which essentially “tribute” was paid by these foreign countries to their respective European masters, as thereby the necessary price that they had to pay in order to have some sort of semblance of at least a modicum of control of their destiny and sovereignty. After all, those countries that did not have the required armaments to successfully defend themselves, had little choice but to accept the terms so dictated to them.
There was a time when France owned significant portions of North America, of which some of that land subsequently became a part of Canada; whereas, other parts of that land were subsequently purchased by the United States as in the Louisiana Purchase. Yet, we do so find that France in the 19th century, through Napoleon III, believed that it was still strategically important to have a footprint in the Americas, and thus thought that during America’s bloody civil war, that the time was ripe to therefore insert their own Monarchy into Mexico, through the usage of the Austrian archduke Maximilian and the Belgian princess Carlota to be the King and Queen, respectively, of Mexico. So, despite the fact that Mexico had its own republic, France brought 30,000 French troops from overseas in order to accomplish their mission to conquer Mexico and therefore to claim such for their newly installed King, via the protection and strength of those French troops.
While the whole event to takeover Mexico through the aegis of France, under the noses of the divided United States, and to thus push aside and squash any Mexican resistance, might have seem to most sensible people, to be fanciful and imprudent – France went ahead and did this very thing. While it is true that France did not actually conquer Mexico, it did lay claim to its biggest and most vital city, that being Mexico City, and did, in fact, get some native support from those Mexicans believing that the Monarchy as structured by France, would be of benefit to them. However, for the vast majority of Mexicans, such was seen for what it was, an invasion; and therefore, in such a large country, 30,000 French troops would never be enough force to pacify and to thus conquer Mexico, completely. Additionally, there was the problem that the United States had not forsaken and had no intention of forsaking its Monroe Doctrine, and therefore had absolutely no intention of permitting France to involve itself in the sphere of what America considered to be its own exclusive influence. However, history tells us, that a showdown between a combination of Mexico and the United States v. France did not occur, because Napoleon III, being a practical Emperor, realized that an all-out war between France and the United States, would not end well for France, and thereby, subsequently withdrew his troops from Mexico, which thereby left King Maximilian to his ultimate fate of execution and the end of his short reign.
So then, by declaring and subsequently enforcing its Monroe Doctrine in 1823, the United States placed itself in the position in which ultimately neither of its two contiguous countries were thereby controlled by foreign interests and of which, we so find that each of these respective countries, are presently on excellent terms with America