used to be... now it's fascism vs. center-right

Is it really center-right? I think it is more far right and facist extreme right. Atleast when observed from scandinavia

There is but you have to think of each party as having sub-parties within them. There aren't external coalitions between parties but internal coalitions within the parties.

So a guy like Bernie Sanders is left, though not technically a Democrat, he caucuses with the Democrats effectively creating a coalition. There are many members within the Democratic Party that are also left wing, and others that are center, and others that could be considered right wing.

The Republicans are similar, but have an internal coalition with the far right MAGA faction. Which causes them a lot of problems.

The primary system is effectively a run off system which is used to determine a final two candidates to vote for in the final election. This system is old and has some bizarre traditions and has vulnerabilities to there being a third party spoiling everything.

Obviously it's a crusty system that developed without planning, but the the Presidential election it's not that dissimilar to France's run-off system, just takes more time. And the legislatures having coalitions between people with different politics happens everywhere, it's just happening within the parties and requires people to vote in primaries to get more representatives that have similar views to their own to make up a greater percentage of the coalition (which also happens everywhere).

In fact having coalitions within a party gives people more information when voting. If I'm voting for one of a dozen parties I don't have a say over how a coalition is formed after an election. Someone declaring which coalition they intend to be a part of before the electorate votes gives the electorate both a say as to which individual they want (via primaries) and which coalition they want (in the general election).

That's why OP wrote "leftist" instead of leftist.

yeah pretty much

This isn't true in a global sense, nor is it true in a practical sense. There is a left in America, but it is tiny and rarely successful. Most liberal democracies are to the right of American Democrats at the global level on most issues. Every country has drifted rightward over the past half century, so the US isn't unique.

It can be both true that there is no true Left with any political power in the US - individual congressional delegates, maybe, but no coalition or party - and still recognize that there remain differences in the parties and differing outcomes from their governance.

It's not anything like the Southpark situation; leftists forget so easily what could - and has - been lost under conservative leadership, that would not have been lost if the person who won the popular vote in the past 6 elections. Women would still have protected body autonomy in all states - that loss was a direct consequence of the Trump administration.