He ends with these worrisome paragraphs.
As a consequence, ideology and partisanship have become merged together in the 21st century in a way that was not the case in the 20th. Liberals mostly were liberals first and Democrats second, and conservatives were conservatives first and Republicans second. Now, it is much harder to maintain those distinctions. There is tremendous pressure on ideologues of both parties to be partisans first and support the party, even if it means compromising their principles.I don't know if impossible is the right word, but certainly deals are more difficult to come by than they have been in the past.
This, I believe, is at the root of the current impasse. Purely partisan fights have been suffused with ideological fervor, thus making deals impossible for now.