Taxing Wall Street

I liked David Stockman's op-ed in the NY Times. I agree that restoring health to our economy and society requires the rolling back of Wall Street's influence and power. How can anyone maintain that Wall Street is doing anything productive? It's a place of out of control greed and speculation that is no long related to productive activity. Although I don't like high taxes and regulations, it's important to control such a potentially destructive force that can derail the whole economy. We should give freedom to productive areas of the economy where individuals and companies are actually provided productive goods and services but not to parasites and speculators who can bring down the whole economy.