The UCR https://en.wikipedia.org/wiki/Radical_Civic_Union is nominally a member of the Socialist International, and many decades ago was roughly aligned with Socialism, but in recent decades their politics mostly favor big landowners and other big businesses. Instead of running their own presidential candidate in 02023, they backed the mano dura Patricia Bullrich, notable for being the only major candidate more right-wing than Milei; he made her his Minister of Security. They did hold the presidency for two years until the crisis in 02001, and previously with Alfonsín in the 80s. They've voted in favor of a lot of Milei's initiatives in Congress; https://en.wikipedia.org/wiki/Argentine_National_Congress lists them as "independent".
Argentina has never had a Socialist President.
There hasn't been a mainstream Socialist party in Argentina in decades.
The PTS https://en.wikipedia.org/wiki/Socialist_Workers%27_Party_(Ar... has four seats in the Cámara de Diputados and zero seats in the Senate. The PO https://en.wikipedia.org/wiki/Workers%27_Party_(Argentina) has one seat in Diputados and zero seats in the Senate. The PCA https://en.wikipedia.org/wiki/Communist_Party_of_Argentina has zero seats in Congress.
https://en.wikipedia.org/wiki/Hermes_Binner was the first (and I think only) Socialist governor of an Argentine province, from 02007 to 02011, and he died in 02020.
The UCR https://en.wikipedia.org/wiki/Radical_Civic_Union is nominally a member of the Socialist International, and many decades ago was roughly aligned with Socialism, but in recent decades their politics mostly favor big landowners and other big businesses. Instead of running their own presidential candidate in 02023, they backed the mano dura Patricia Bullrich, notable for being the only major candidate more right-wing than Milei; he made her his Minister of Security. They did hold the presidency for two years until the crisis in 02001, and previously with Alfonsín in the 80s. They've voted in favor of a lot of Milei's initiatives in Congress; https://en.wikipedia.org/wiki/Argentine_National_Congress lists them as "independent".