Heh. You could have Argentina join the Axis invade Uruguay and Brazil thereby giving America the casus belli needed to declare war on the Axis. Despite early gains in southern Brazil, the introduction of American forces dooms them and the SA theater becomes a decisive allied victory withen 3-5 months of the conflict's start. The US promptly provides Argentina with the aid and investment needed to both modernize their economy and develop as a liberal democracy. High economic growth rates continue throughout the postwar era and by the late 80's Argentina's GDP is somewhere between that of Spain or Italy.