Myron Proudfoot
Master Poster
Comes with the territory of actually being a "big tent" party.
I would argue that it also comes with having fewer members with an authoritarian personality. Authoritarians like to follow authority, feel safer accepting the opinions of their "superiors", and, put simply, follow orders better.
I've been an election officer for the past 10-12 years in my county and I have noticed that it's the republican reps that are the most rules-driven-- "Why does your voter registration say "John Paul Smith but your driver's license says "John P. Smith? They have to say the same thing!" A few personal examples are not proof of course, but it does fit the historical model. Historically, authoritarians are found on both the hard left and the hard right, but the hard left is very tiny in the US, so they're really concentrated among republicans.
There is a great study available online as a pdf on the authoritarian personality. I'll have to see if I can find it to link to it here.