During the health care debate, liberals argued that government had a moral duty to enact legislation that expanded health insurance among lower-income individuals. This was rooted in the assumption that obtaining health insurance translates into improved health. But a landmark study published in the New England Journal of Medicine dramatically undermines this assumption and shatters the rationale behind the law’s Medicaid expansion.

In 2008, Oregon expanded its Medicaid program, but because the state could not cover everybody, lawmakers opened up a lottery that randomly drew 30,000 names from a waiting list of almost 90,000 and allowed them to apply for the program. This created a unique opportunity for health researchers, ultimately allowing them to compare the health outcomes of 6,387 low-income adults who were able to enroll in the program with 5,842 who were not selected.