Representative-elect Alexandria Ocasio-Cortez, the New York Democrat who has become a darling of the progressive left, was quoting from an article in The Nation about “massive accounting fraud” committed by the Pentagon from 1998 to 2015. But her suggestion that the $21 trillion in military transactions could have “already” paid two-thirds the cost of a “Medicare for all” health care system goes beyond what the article reported — and is misleading.