The amount of South America allocated to Portugal in the Treaty of Tordesillas was a small fraction of what ultimately became Brazil, and even the western most estimate from the follow on Treaty of Zaragoza didn't give *that* much more.
So how do we keep Portuguese America restricted to that small portion of the continent rather than making up half of the land of South America?
So how do we keep Portuguese America restricted to that small portion of the continent rather than making up half of the land of South America?