John Roberts, unwitting health care visionary.

The Supreme Court’s decision in the health care case is best understood as an attempt to maximize damage to established legal precedent while minimizing damage to the particular law under consideration. On the one hand, Chief Justice John Roberts wanted to maintain the Supreme Court as a playpen for anti-government sophistry. On the other, Roberts wanted to avoid getting pilloried as a right-wing extremist who doesn’t care whether people get health insurance or not. Out of this jumble of warring impulses, Roberts crafted a ruling that inadvertently strengthens the liberal case for further consolidating health care policy at the national level. The Court is practically begging Washington to take over the state-federal Medicaid program.

Roberts provided the critical fifth vote upholding Obamacare’s most contentious feature—the individual mandate, which will require virtually all Americans to acquire health insurance. He did so by the (slightly circuitous) route of interpreting the penalty for not being insured as a tax. That strategy allowed Roberts to join the conservatives in restricting, at least theoretically, future applicability of the Commerce clause—which horse-and-buggy “originalists” maintain has been, since Franklin Roosevelt’s day, distorted to justify illegitimate government expansion.

More surprising, though, was the decision to strike down a separate provision in the law: the requirement that states choosing to participate in Medicaid, as they all now do, offer the program to a much larger class of people. Such federal mandates are, as a matter of law, utterly routine. The conservative legal case against the Medicaid mandate is weak, since the states have the option not to join Medicaid. The program, created in 1965, didn’t enjoy full state participation until 1982, when Arizona climbed aboard. On practical grounds, governors and state legislators have often complained that federal mandates in general, and Medicaid mandates in particular, impose costly state-spending requirements. But that’s a difficult argument to make against Obamacare’s Medicaid expansion, because the federal government will fund 100 percent of it for the first three years, starting in 2014, before gradually lowering its share to 90 percent in 2020 and thereafter. Prior to the Supreme Court decision, no court had given the Medicaid part of the legal challenge to Obamacare any credence.

Somehow, Roberts was persuaded that the health law’s (prepaid!) liberalization of Medicaid eligibility and benefits was an unconstitutional curtailment of states’ rights. So were four other Republican-appointed justices. And so—most surprising of all—were the Democrat-appointed Justice Elena Kagan and Justice Stephen Breyer. (Their concurrence on this point may have been Roberts’s price for not tossing out Obamacare altogether.)

The argument that Roberts made against the Medicaid expansion is that Medicaid spending had become so large a portion of state budgets—typically 20 percent or more, with at least half of that paid by the feds—that states no longer had the option of dropping out. According to Roberts and his six colleagues, that made the Obamacare Medicaid mandates inherently coercive. Wait, wouldn’t that mean the federal government could never make any future changes to Medicaid? Well, no, Roberts said. Obamacare’s Medicaid mandates were particularly meddlesome because they represented “a shift in kind, not merely degree.”