This challenge requires essentially a Pan-Americanism wank: at least some of the revolutionary republics of the Americas (Haiti, Gran Colombia, the FRCA, Argentina, Chile, Peru, Bolivia, Mexico after the abolition of its monarchy) must form some sort of defensive pact, alliance, or mutual aid treaty.
Bonus points if it lasts more than 20 years and/or fights a war against a foreign power together. Lots of bonus points if you can somehow get the USA to be a part of this, though for that to work, pro-slavery and anti-Catholic sentiment will have to be greatly reduced.
Bonus points if it lasts more than 20 years and/or fights a war against a foreign power together. Lots of bonus points if you can somehow get the USA to be a part of this, though for that to work, pro-slavery and anti-Catholic sentiment will have to be greatly reduced.