"Argentine government is especially bizarre because the party system has historially not made any damn sense at all."

Argentine here. That's just not true, at all.

First, "Peronism" is not a party. "Peronism" is the product of the deep personalism of argentine politics. It's movement very much like a political Christianity: "he tougth us The Way and we must interpret his words". It's like if people in the US that love Ronald Regan started calling his thinking something like "Reganism".

As you pointed out, Republican and Democrats changed their general views over time. The same happens here. The difference is that the Justicialist party (the main "Peronist" party) almost always wins.

Traditionally, the analog to the current Democrat/Republican dynamic was the Justicialist/Radical Civic Union (or "UCR"). The first one was more for economic regulation and general welfare, while the second was less about welfare and more about economic freedom. But the UCR hadn't been relevant for almost 20 years now. In the '90s the Justicialist party took a "economic liberal" turn, a strange one in retrospect, but one that most Justicialists supported because "privatization of public services and more economic freedom, for some specific people, CAN be better for the welfare of the people". How can a left-wing party get away with that? they had power. They already had the left-wing peronists masses, and they could get the votes of the middle-class, who mainly voted for the UCR, with some economically liberal policies. The left/right dynamic was destroyed because one party got to powerful.

That ended badly, with horrible preformance by a heavly subsidized private sector, the inability to compete with foreign products destroyed hole industries, the massive firings created more and more poverty and slums, and a monetary policy that tried to maintain the Argentine peso equivalent to the US dollar without actually creating enough growth to sustain it. Things were starting to smell around '99, so the Justicialist party lost the presidential election against an alliance spear-headed by the UCR. But then everything went south in 2001. We had one of the worst economic crisis in our history, the goverment authorized the banks to not give any money back to the people, which created a massive outcry from the middle-class. After that any reasonable person would ask "And why the fuck would anybody vote for the Justicialist Party ever again?", and that's when Faith comes in. Faith, and the lack of options (after all, the crisis exploded during the UCR-and-friends's watch). People still believed that "Peronism" was the true path, so the Justicialist Party reinvent themselves.

A small faction within the party rose to power with a "go back to the roots" narrative. And they did, they won the 2003 presidential election under the name "Front for Victory", registered as a "new party". The failure of the "Neoliberal model", the model their own party had apply, gave them the perfect traumatized population to apply a left-wing, demagoge, and nationalist narrative. And because we like our personalization in our politics, we call it "Kirchnerism", for the faction's leader Nestor Kirchner (president of the country for two terms). He died in 2010. The current president, Cristina Kirchner, was his wife...

And that's it. We had classical rigth/wing dynamic until the left-wing party got so powerful that could do whatever they wanted, and failing miserably trying to keep everybody happy. They gave sinking ship to the traditionally right-wing party, and when shit hit the fan they lose their last chance to prove the people they were capable, dooming them for ever. Then, the left-wing party went trougth a rebranding process and started ruling again, without any real oponents, with all the political power. Just now we have some contenders for The New Rigth Wing Party (UCR is pretty much dead now), but only time will tell.

Oh, and of course now we have a new generation of kid rised in the '00s inside the goverment-funded propaganda machine, kids that wear T-Shirts that say "With Cristina, Without Doubts"... yeah.