“Even utopias need a tax clause. For example, we could start with a transactions tax to rein in the financial industry. Back in 1970, American stocks were still held for an average of five years; forty years later, it’s a mere five days.21 If we imposed a transactions tax – where you would have to pay a fee each time you buy or sell a stock – those high-frequency traders who contribute almost nothing of social value would no longer profit from split-second buying and selling of financial assets. In”