Here is a cute article about why the rich support Democrats, and the middle class keep electing Republicans. Allan Nadel, writing in the American Thinker, takes the view that the rich support Democrats because they know something we don't. As he says, if he knew what they know, maybe he'd be rich too.
I suspect it is quite another matter entirely. The people who earn wealth typically support Republicans, it is their children and grandchildren who support Democrats. The issue, in my view is guilt, a sense that they have wealth and did nothing to earn it. Their good fortune is purely a matter of luck, the luck of being born to wealthy parents. Seen from that point of view, inherited wealth can engender a sense of guilt, a sense that life is unfair and that government should engage in redistribution.
This brings me to a try at stating Cotton's Law of Political Orientation Among the U.S. Affluent:
Individuals who earned wealth, through a life of hard work and good choices, tend to believe others could have done the same had they but tried. Seeing themselves as unlike the poor, such individuals tend to support Republicans.
Individuals who see their wealth as the result of good fortune or having the right parents don't believe others could have achieved the same outcomes with hard work and wise choices. Seeing themselves as like the poor in everything except outcomes, such individuals tend to support Democrats.
One postulate of this law is that the hyperrich, for example Bill Gates or Warren Buffett, understand that they were not vastly more talented than the merely rich. Since luck played a big role in their hypersuccess, they lean left. In other words, hyperwealth leads to hyperguilt.
In our state, Wyoming, only one county voted for Kerry and Edwards: Teton County. It is the county with the most inherited wealth. Oddly, it is also where Vice President Cheney has his home.