The US is the model for settler-colonialism in the modern era, itself being explicitly based on the Roman empire, with a slave-holding aristocracy holding political power, and granting free land and status to those willing to participate in its imperial project.

There have been challenges throughout US history against this rule by aristocracy, but all of them lost at various points, and are now on life support. It genocided its indigenous inhabitants and stole their land. The Civil war was a challenge between two right-wing systems: capitalism and slavery, although slavery was reinstated during the reconstruction era. Its communist-left was purged and eliminated by the 1960s, its union movement predictably died soon after in the 1970s, the anti-war left died in the 1980s.

There has never been the equivalent of a "red-scare" but for the right-wing, because the US is a right wing country and does not permit a public platform of left-wing views. Its a one-party state where both parties are "fluid", one acting as the "foil" / controlled opposition against the one which currently reflects the more overt interests of its aristocracy.

I highly suggest reading Settlers, an Indigenous people's history of the US, and Zak Cope - Divided world divided class, for some of the underpinnings of the US's "master-race democracy".