The problem with using a distorting social lens.
A common trope of commentary, both inside and outside the US, for some years now (even before the Trump-apocalypse) was that the Republican Party had shifted rightwards. The trouble is, this is mostly not true.
The views of Republican voters has changed very little in recent decades. The views of Democrat voters have shifted notably to the left. Republican voters have become more consistently conservative in their views, which has pulled the median Republican voter away from the centre. But the shift away from the centre of the median Democrat voter has been much stronger. As the above graphic demonstrates, in 2016 Democrat voters were much more clustered away from the centre in economic policy, and somewhat more clustered away from the centre in cultural politics, than were Republican voters. Movement in Democrat opinion has been driven by shifts among liberal and college-educated Democrats, which began before Trump’s candidacy.
So, from whence comes this view that the Republicans have become “much” more right wing?
Partly, as Damon Linker points out, from increased used of brinkmanship by the Congressional Republicans. But this shift in tactics is not really a shift in opinion (though it may reflect a consolidation of opinion among Republicans).
Mostly, however, it comes from the mainstream media, especially the “quality” media. The views of the mainstream media, especially the “quality” media, have shifted sharply, and increasingly intolerantly, leftwards. The result is, even with minimal shifting among Republicans, the distance between the views of the mainstream media, especially the “quality” media, and those of Republicans has steadily grown. As the mainstream media, especially the “quality” media, is the lens through which many Americans, and even more international media and their audiences, see US politics, the increasing expression by many American journalists of their growing distance from Republicans have created the illusion of the Republicans becoming “much more” right wing.
It is a parallax effect. If there are two poles, and you are moving so that one seems closer and closer and other seems further and further away, it can look as if the receding pole is shifting, when it is your point of view that is actually shifting. Similarly, if you are retaining the same distance away from one pole that is shifting further and further away from another (stationary) pole, that can also create the illusion that the stationary pole is moving.
Looking at US politics through a mainstream media, particularly a “quality” media, that has been shifting leftwards, has created the illusion of shifts in Republican opinion that are much larger than they actually have been. Meanwhile, the same process has obscured the reality that leftward shifts in Democrat opinion have been significantly larger than any rightward shifts in Republican opinion.
The collapse in advertising revenues has created something of a “go broke, go woke” phenomena in the US media, where collapse in ad revenues has led to smaller newsrooms that are more easily captured by the intolerant conformity of recent university graduates. This is making much of the media an ever more distorting lens through which to view US politics. Or US society in general. Or public policy issues.