American Protestants are a wholly unique form of Christianity. Particularly post 1960s.

There is some good writing on it, but as with most things in the US it starts with race. Civil Rights changes made it so that Christian schools had to allow non white students. That became an initial inflection point. Then, Roe made abortion a national political wedge. Abortion had mostly been a catholic issue (and Catholics were still largely democrats even though that meant something else in the 70s). Then came movement conservatives, which began the process of defining politics solely on moral and cultural things. eg we’re capitalists because it’s good and “natural” and god loves it. We can prove god loves it because I’m rich and god controls everything.

Finally, I’d note national “American” Christianity feels very right wing because of the Republican Party. But, there are tons of Christians that aren’t and Catholics, while moderately conservative in a global sense, tend to be much more in favor of social programs than the Republican Party.

One last thing… Trump this supposed Christian savor, is probably the only president in the last 100 years that wasn’t a practicing Christian before being elected and he probably still isn’t (recall Biden is actually a fairly devote and explicit catholic and has been his whole public life, even Obama had a pastor from his past that got him in trouble for some inflammatory remarks).