With the Republican Party committed to a gold commission and the Federal Reserve committed to easy money, a substantive debate about the principles underpinning our monetary system is finally in the offing. For sound money to carry the day, Republicans will need to do more than point out the still-hypothetical risks of easy money. The GOP will have to detail the harm that the middle class has already suffered as a result of a policy of low but persistent levels of inflation.

A little inflation appears...