As you can see here, it’s not even accurate to say that the “Warren Court” is a liberal outlier; in Scot Powe’s phrase, it was really only “History’s Warren Court,” that is the Court beginning in 1962 when Goldberg replaced Frankfurter, giving the Court five fairly reliable liberal votes with Douglas, Warren, Brennan and Black. (Black, admittedly, stayed on the Court at least a decade too long and began a “you can’t take the boy out of Alabama” late phase, but replacing Clark with Marshall limited the damage.) The Warren Court of the 50s wasn’t particularly liberal, particularly on civil liberties.
But anyway that’s it. Thanks to the filibuster and then resignation of Fortas, conservatives captured the Court in 1969 and haven’t looked back, other than a couple of terms where the issue mix made Kennedy look more liberal than he was (and note how in his last term before gifting his seat to Donald Trump he cast essentially the same votes as paint-by-numbers reactionary Brett Kavanaugh would have.) The Burger Court was more reactionary than is commonly understood and the Rehnquist Court was worse. And we’re now going to have the most consistently conservative Court since the New Deal.
And for Republicans, the beauty of it is that the Court has been their ally and yet they’ve been able to use its alleged opposition as a mobilizing tool, getting the best of both worlds. The Kavanaugh hearings seem to have finally gotten more Democrats to understand what’s happening, but alas this will be too little too late.