Cisplatine War

Before the war
Cisplatinaball wanted to reunite with the  United Provinces, the  United Provinces didn't liked the idea because the orientals were federals, but at the end she decided to help the province.

The war
The  United Provinces took advantage of  Brazil's instability to attack, these two had a very close fight and a lot of the battles ended up being inconclusive.

On the land battles, the  United Provinces won all the main battles (Battle of Sarandí and Battle of Ituzaingó). Argentina was able to advance a lot through  Cisplatina, not giving opportunity to the  Empire of regaining terrain. But there were a lot of inconclusive battles and never invaded the capital.

On the sea battles the  United Provinces and the  Brazilian Empire won one of the two main battles,  Argie won the Battle of Juncal, while  Brazil won the Battle of Monte Santiago. And most of the rest of the battles were inconclusive. Despite the close fights the argentine navy was small and ended up in a bad state after the war.

UKball  forced  asked for a negociation, and both accepted. The  United Provinces gained some land on Misiones and  Cisplatinaball became  Uruguayball against it's own will.

Fun fact: during the Battle of Ituzaingó  Argentina theft a marching song about the battle that  Brazil was making in case of winning the fight. Argentina won and made the march one of her presidential emblems and mocks  Brazil even to this day by playing the march.