http://www.ted.com/talks/richard_wilkinson.html
This is an interesting talk that I watched last year. There are some interesting questions that aren't fully addressed and some that are addressed tangentially, but the basic, fundamental, statistical result is this: the more economically unequal a society is the more problems that society experiences. If you look back in time, you also will see this as a repeating pattern. The French have had revolutions because of, essentially, economic inequality. The Roman and other empires have fallen with unequal wealth distribution as a contributory factor.
I don't expect the more Republican amongst you to believe it. To a Republican, the notion that you get out of life what you put into it might be true on a local scale, but you as an individual on a broader scale also benefit by helping the poorest amongst you. But this is empirical evidence and quite convincing when you actually think about it instead of tossing it aside because it conflicts with your narrow political ideology.
EDIT: I also realise this is somewhat tangential to the topic at hand, but the topic of healthcare has of course cropped up. And the point of this talk if you understand it is that redistributing wealth - even through social welfare programs - can help a society overall. To some this is counterintuitive - that is essentially the underlying point of a Republican as I understand it - but I am reminded of a quote: "Not all that counts can be counted; not all that can be counted, counts." Providing such things as social healthcare may in a z = x-y mathematical way seem bad, but the *effects* of doing so cannot always be put into a simple mathematical formula as the human condition isn't something which can be adequately simulated or computed.
Note: I've had wine. I'm kinda tipsy. Don't take everything literally - just put aside political ideology and seriously think about the concept.
To those who understand I extend my hand; To the doubtful I demand to take me as I am.