Republican tax reform could have been better. An ideal reform, originally proposed by Paul Ryan would have produced a of 20.5 percent increase in the nation’s capital stock and a 6.8 percent increase in GDP. Wages would have increased by 6.3 percent for high-income workers and by 7.5 percent for low-income workers. The reasons: a highly elastic global supply of capital, which moves across borders at the first sign of a tax advantage and the inefficiency of the U.S. corporate income tax, which, as of 2014, our year of calibration, had a very high marginal, but very low average tax rate.