“Nothing is so permanent”, noted Milton Friedman, “as a temporary government programme”. Friedman died in 2006, a couple of years before Fannie Mae and Freddie Mac, two enormous government-sponsored enterprises (GSEs) that provide liquidity to the American mortgage market, were bailed out during the global financial crisis. The firms were taken into “conservatorship”, a form of temporary government control. It has now been in place for almost 17 years.