There is an interesting essay by Dani Rodrikhere, commenting on the recent reversal policy on the part of the International Monetary Fund. The reversal concerns the legitimacy of controls on capital mobility of various sorts. At the end of the piece Rodrik endorses "a global financial transaction tax. Set at a very low level – 0.05% is a commonly mentioned rate – such a tax would raise hundreds of billions of dollars for global public goods while discouraging short-term speculative activities in financial markets." You can find the web page of a group pushing this "Robin Hood" Tax here. And you can find earlier, related columns from Rodrik here and Paul Krugman here
