South-American military History

Yes , Windischer we had ! 
And don't remember exactly  right now , but USA started a friendly relationship with Brazil because they feared a naval invasion .

The defense minister of USA ay the time of paraguay war said that it would be a good thing befriend with Brazilian Empire,  because if Brazil  had wanted to invade USA,  Riachuelo boat could be able to cannonade Washington.  Riachuelo boat  was the unique boat able to sail rivers and sea.
Some historians say that navy pattern of USA was made by the fear of brazilian Empire invasions.
Imperial Navy was the pride of D. Pedro II, our emperor. 

Earl, the main question behind Spanish colonies dissolution was the several internal conflicts between the political class. When Spanish colonies became independent, Simon Bolivar and San MArtin (heads of independence uprising) decided to create a unique Republic, gathering all the former colonies. But local governant weren't really in this idea, because it would reduce their local power. So, after decades of independance uprisings in spanish america, they decided to maintain it as we know. An example: have you heard about Gran Colombia? It was formed by Colombia, Venezuela and Panamá. Local politics were losing their power, so they decided to separate. 
Another point: Simon Bolivar and San Martin didn't have enough power to maintain a big country. They  weren't abble to keep the stability of a large country, with a lot of independance uprising coming arround and borders dispute.
Brazil was different. Brazilian independance uprising came from a Emperor, with enough power to maintain the stability and 
protect borders and stifle internal independence revolts. If Brazil hadn't had the monarchy, we would be a lot of tinny republics, like spanish america.
The same thing is aplicable to Germany. Until they had Bismarck and Wilhelm I, with enough power to remove french influence and claim the sovereignity over all those lands, they were just a mount of tinny countries. 
USA is a little bitty different haha, I think. They were founded as a great union of some republics, and they decided to maintain a Federal Institutions to guide their bases. They undestanded that together they are stronger. Eventhough, USA just assumed internal supremacy after Civil War. Dixies mantained their independance for a year untill Union started a recovery war, what shows that Union was initially according with secession riots, respecting their own sovereignity. But , after some time, they decide to dont accept they independence and invade it in a recovery war. I think its because they decided  claim the union supremacy in a internal sight, as well as Brazil, German and Italy. 
The most importat thing in a Country creation is the power and where it is located.