Supply side economics is widely misunderstood, by both fans and detractors. True supply side revolves around focusing on the basic ability to supply.

Liberals get it wrong, because they assume demand alone can create wealth. When you look at most of the world, you see this is inherently not the case. Billions of people want and even need all sorts of things that are beyond them, because noone is able to supply it at a price within their means.

Anyhow, Keynesian economics is mostly crap. Austrian economics is far and away the most rational, Von Mises speaks with the most clarity and sense.

The bottom line though, is people have to be able to produce. When you stifle that ability, you get Communism - not in the "left vs right" rhetorical sense, but in the sense that Communists were all poor as shit because the gov't, fundamentally did not ALLOW people to create wealth. Wealth can be created, and not simply distributed.... but the gov't can never achieve it, and never has achieved it.

The most gov't can hope to do, is protect an environment where people are able to create it themselves.

For who could be free when every other man's humour might domineer over him? - John Locke (2nd Treatise, sect 57)