Greg Mankiw points to Matin Feldstein: Marty runs some numbers.
Brad DeLong checks the math. Oops:
Martin Feldstein Accidently Proves Either (i) 152 > 186 or (ii) It Is Mathematically Impossible for Romney to Keep His Tax-Policy Promises: The fact that he sought to prove otherwise and wound up confirming the Tax Policy Center's conclusions purely by accident gives me additional confidence that the TPC knows what it is doing. ...