> That's not how the Overton Window works. The Overton Window says what kind of opinions are socially acceptable
"Socially acceptable" is, necessarily, relative to some defined group.
Especially in a political system with limited major parties and partisan primary elections (especially if they are closed, but even if they are open in theory but tend to attract a specific mostly-stable community in practice), and a substantial population that participates in neither parties primaries, considering the Overton Window within each party and/or ideological identity group as well as the "national" Overton Window can be useful. The GP comment could be rephrased without, I think, change of meaning as "the Overton Window of the community of the ideological Right and/or the Republican Party has moved relative to the rest of society such that it excludes much of the window as viewed by those not ideologically tied strongly to the Left or Right faction".
"Socially acceptable" is, necessarily, relative to some defined group.
Especially in a political system with limited major parties and partisan primary elections (especially if they are closed, but even if they are open in theory but tend to attract a specific mostly-stable community in practice), and a substantial population that participates in neither parties primaries, considering the Overton Window within each party and/or ideological identity group as well as the "national" Overton Window can be useful. The GP comment could be rephrased without, I think, change of meaning as "the Overton Window of the community of the ideological Right and/or the Republican Party has moved relative to the rest of society such that it excludes much of the window as viewed by those not ideologically tied strongly to the Left or Right faction".