Writing in the Wall Street Journal, Martin Feldstein, an economist at Harvard University, argues that "behavioral responses" of taxpayers to the cuts in marginal tax rates enacted in 1986 resulted in "an enormous rise in the taxes paid, particularly by those who experienced the greatest reductions in marginal tax rates." How is it possible for cuts in marginal tax rates to result in an increase in total taxes collected? What does Feldstein mean by a "behavioral response" to tax cuts?