Parties are now tribes. Truer now than in the past?
In the essentialist theory, ideologies are unchanging, transcendent principles, while parties are evolving social organizations that can be “captured” by the ideologies. In the social theory, by contrast, ideologies don’t capture parties; parties capture ideologies—that is, they redefine them. Once again, research supports the latter: what is considered “right-wing” or “left-wing” is simply whatever the Republican and Democratic Parties happen to stand for at a given moment. Left-right ideologies are tools of self-delusion—they let us indulge the fantasy that our partisanship is principled rather than tribal, i.e., that there is some noble ideal connecting all the distinct and unrelated issues that our party happens to support. But essentialist predictions do not hold up to reality.