This commentary, written by Richard Epstein & Mario Loyola, originally appeared in the National Review Online on July 30, 2012.

Precedent is the glue that holds the American legal system together, giving both adaptability and predictability to the decisions of our courts. When a precedent is good, it’s great, but when it’s bad, its effects can be terrible. The real story of the Obamacare decision is that it was driven by flawed precedents that should have been modified long ago. To make matters worse, the Court’s decision created a new precedent that could do lasting damage to the Constitution if it is not reversed.

Those flawed precedents have a couple of things in common. First, they replace binary, categorical, yes/no decision rules with tests that rely on indeterminate sliding scales, leaving legislators and the public little guidance for the future. Second, they blur important limitations on the power of the federal government, thereby undermining the accountability and institutional competition that were the genius of the original constitutional scheme. In Obamacare, the Court not only missed an important opportunity to fix these problems, it entrenched them more deeply.

The individual insurance mandate was unprecedented. The federal government had never before claimed the power under the Commerce Clause to force individuals to purchase something merely because they were alive. A bare majority of the Court properly refused to uphold the mandate as an exercise of the federal power to regulate interstate commerce. The Framers might have wondered: How did we ever get here? The Constitution made it unequivocally clear that the federal government could not regulate the “purely internal commerce” (in the Supreme Court’s phrase) of any state, a position to which the Court held adamantly for 150 years.