I can use Bruce Schneier's Liars and Outliers as the basis for another take. A basic question in the book is how human society is able to scale above the level where we can all recognize one another.
For example, in a large battle involving people you have never met, how do you know who is friend or foe? Soldiers' uniforms provide the answer. If you are on the Gray team, then you expect Blues to shoot at you but to be safe from the guns of Grays.
Ultimately, the affiliation heuristic derives from a scaled-up model of tribal shunning. You know that if you were shot at by a fellow Gray, he would be punished by the rest of the Gray tribe.
In commerce, Schneier gives the example of Quaker success in 18th century capitalism. If everyone (not just Quakers) knows that Quakers will shun other Quakers for dishonest, dealings, then as long as you can determine that someone values his membership in the Quaker community, you can count on him to be honest. Hence, the affiliation heuristic. A lot of long-distance trading was famously undertaken by ethnic minorities, where the affiliation heuristic substituted for being able to observe the other party at close range.
In fact, the affiliation heuristic is deeply embedded in commerce. You trust the doctor because you see her license on the wall, and you assume she does not want to lose it. You see her diploma from a leading medical school, and you assume that the school, too, would not want to risk its reputation by graduating a poorly-trained doctor.
And yet, I argued here that the affiliation heuristic is invoked insincerely, for manipulative purposes. We see that in marketing and in politics. Marketing campaigns sometimes try to use affiliation to get you to buy a product. This will make you just like X! If you don't have it, you will be like Y! Around here, the Washington Post slogan was (still is?), "If you don't get it, you don't get it."
Politics is very much a game of affiliation. Voting can be predicted very well on the basis of location and ethnicity.
What motivated my earlier post on the affiliation heuristic is that I generally am bothered by the way politicians and pundits deploy it. The Kochs are notorious for being notorious! Don't affiliate with them! President Obama once hugged a radical! Shun him! Steven Landsburg sides with Rush Limbaugh. Condemn him!
I find that ugly. Shunning someone's political positions is fine. But I don't want to see anyone shunned as a person. Don't tell me I can't associate with X because he is a liberal. Don't tell me I can't associate with Y because she is a conservative.
There are two arguments made for taking Ed Crane's side in his dispute with the Kochs over Cato's board. One argument is that being associated with the Kochs will be bad for Cato. That is the ugly use of the affiliation heuristic that I would prefer to fight than to accept.
The other argument is the fear that, under the Kochs, Cato scholars will lose their ability to speak out on issues where they are to the left of the Republican Party (indeed, often to the left of the Democratic Party): immigration, foreign intervention, civil liberties vs. the threat of terrorism, gay rights, drug laws, etc.
If that fear is justified, then the Crane side has a case. But my instinct all along has been that this is a personality conflict, not an ideological one.