The Overton window is an approach to identifying the ideas that define the spectrum of acceptability of governmental policies.

Overton window is an idea's political viability depending mainly on whether it falls within this range, rather than on politicians' individual preferences

I also like the other similar technique or names in the "See also" section of Wikipedia:

Creeping normality
Hallin's spheres
Opinion corridor
Moral relativism

According to Joseph Overton the window frames the range of policies that a politician can recommend without appearing too extreme to gain or keep public office given the climate of public opinion at that time.

https://en.wikipedia.org/wiki/Overton_window

Unthinkable
Radical
Acceptable
Sensible
Popular

Policy

Popular
Sensible
Acceptable
Radical
Unthinkable