Studies don't prove that, Summers says. And most economists -- including Milton Friedman, who shockingly but persuasively argued that "licensure should be eliminated as a requirement for the practice of medicine" -- see the scam behind the Nanny State smoke.
They know that occupational licensing is almost always a result of political lobbying by the very profession being licensed. And it is a sneaky way to use government power to protect the economic interests of incumbent doctors, lawyers and pesticide applicators.
By making it harder and more expensive for new doctors, lawyers and pesticide applicators to enter the market, competition and the number of practitioners in each field are artificially - and unfairly -- held down and salaries, prices and profits are propped up.
Consumers get robbed every day by this venerable public-private racket. So do those who'd like to become dietitians or auctioneers but can't afford the time or money for training or certification requirements. So does society, which gets less economic growth and innovation.
It's maddening. Because of occupational licensing, today Abe Lincoln couldn't practice law, Florence Nightingale couldn't be a nurse and Albert Einstein couldn't teach physics in a public school in America.
But don't despair. Our freedom to work isn't totally lost. Except for in Iowa, where you do need a license, any American can still grow up and become a manure applicator without getting the government's permission.