Horseshoe theory. Very little separates the extremes from each other.
The Overton window has been creeping to the right for the last half century, so traditionally leftist views like freedom of speech, a right to privacy, and being anti-war are now outside the window. Anyone who still holds those values is effectively far right, say the horseshoe-calling centrists.
Nonsense!
50 years ago you could have opinions on two different subject on the left, but in 2023 one of those opinions could have flipped but the other stayed the same.
Both the horseshoe and Overton window do not really account for these topical flips of opinion which renders both inadequate for explaining the ebb and flow of politics.