Good PL post relative to a study that shows (unsurprisingly) that when Republicans are called "extreme", it is relative to CURRENT Democrats -- which have moved FAR to the left from what they were even ten or twenty years ago ... witness Hillary tacking LEFT to compete with Bernie Sanders, an avowed Socialist, while her husband Bill, tacked RIGHT and the whole Democrat push of the '90s was CENTRIST!
Not anymore ... it is now EXTREME! The assumption of the left or "progressive" view is that a nation ALWAYS moves left -- moving left, to more government, more control, more regulation, less personal freedom in every area save morality, etc is "progress". The left assumes that the ultimate state of mankind must be absolute control from a centralized authority with all people living in some relation to that authority -- both enslaved and completely dependent at the same time (which is a definition of slavery).
The assumption though is that if you "properly educate" the masses, that total enslavement to a collective cause is the proper state of the mass of humanity -- once people are "sufficiently educated", they will willingly salute their complete dependence for everything including their daily direction from the state. This has all been covered in plenty of fictional works -- from Orwell's "1984" to Huxley's "Brave New World", as well as in plenty of works of non-fiction -- "The Gulag Archipelago" leaps to mind, as well as the excellent reality fiction "The Lives of Others" about East Germany.
This constant slide to the left has been going on in this country at least since Wilson, and really before. It is enough to make one wonder if it really and truly actually is inevitable!