I don't believe that a flat income tax is really an answer but I do agree that a single source of tax revenue would be far more efficient. I think a simple sales tax should be levied on everything that way they government doesn't have to know how much money I make and they don't have to employ people to audit income tax returns. The government should promote the welfare of its citizens and if I fail to report my income correctly then I become a criminal. If tax was based solely on consumption, then the more gas, food, clothes, electronics I buy, the more tax I pay. This doesn't over tax the poor because they simply won't buy as much stuff. If I make more money, I am not taxed at an increasing rate, I am taxed based only on what I buy, which would be more than when I was poor. Give people their full income to spend and they will spend it and you can still collect your taxes while promoting more commerce.