Is David Cameron's Austerity Three Times as Bad as Brexit?

That's the question millions are asking, or at least the one they should be asking. The OECD recently did an analysis of the economic consequences for the U.K. if it decides to leave the European Union. It concluded that it would cost the country 5.1 percent of GDP in its central estimate. Other analyses have arrived at similar estimates. Such estimates have been cited by right-thinking people everywhere as a powerful argument against the U.K. leaving the European Union. (It is.)

But Brexit i...