The rich create jobs for the poor and middle class. If we alienate the wealthy and/or tax them too heavy, we will lose out on their ability to produce jobs.
And there is some truth to that claim. However, it is only one way to look at the economy of our economy. It is also a severely limited top-down approach.
Look at it from another view:
The poor and middle class sacrifice to create wealth for the rich. If you alienate them (which is the de facto mode in the world and the US), you lose your ability to gather your wealth. And, you may face a terrible, terrible revolution.
*And by this I don't mean the Tea Party or Noise-Maker crowds. I'm talking about several friends who are sensible people and sincerely want to help the poor and disenfranchised. They are attracted to fiscal conservatism because they're convinced it's the responsible and best way to lift all boats.