Last time Paraguay tried to invade Brazil, they lost 3/4 of their country, and every male between the ages of 8 and 80 was executed.
75% of the population perished; this is one of the greatest "genocides" (we argue it was not a genocide, as Solano used them in the military) in recorded history, and we never shy away from it. Paraguay war was the price Brazil had to pay to buy peace to this very day.

I know a thing or two about the war because some of my ancestors were hired as German mercenaries to fight for the emperor. The pic related is one of them.