I'd be very interested in finding out what political positions historians generally hold, or if there is any generally held position. Have there been any surveys done in this area?
There is a book called, The Marketplace of Ideas by Louis Menand, which is a history of the postwar American academy. I looked for my copy, but I couldn't find it. I'll update it if I do. I can tell you that there is a chapter called "Why Do All Professors Think Alike?" There are some figures. Basically, the academy (especially the Liberal Arts) as a whole skews pretty heavily to the left. At least on a personal level, in my experience in a rather large university history department, I can say that this is pretty much true.
This visualization, based on campaign contributions data, has historians listed under two categories: Social Science and Academia. In the first historians are 88% Democrats and 12% Republicans, in the second history professors are 95% Democrats.
Also, there is a paper based on surveys of academics. Predictably, among historians 80% are Democrats and 17% more are Independent.