Are there five votes on the current Supreme Court to strike down the health insurance mandate as a violation of Congressional power under the Commerce Clause? New York Times legal reporter Linda Greenhouse doesn't think so:
The challengers invoke and seek to build upon the Rehnquist court's "federalism revolution" that flowered briefly during the 1990's. In a series of 5-to-4 rulings, the court took a view of Congressional authority that was narrower than at any time since the early New Deal….
But Chief Justice John G. Roberts Jr. is not William Rehnquist, and Justice Samuel A. Alito Jr. is not Sandra Day O'Connor. John Roberts has made his career inside the Beltway ever since coming to Washington to clerk for Rehnquist. As for Sam Alito, I don't believe that apart from a brief part-time gig as an adjunct law professor, this former federal prosecutor, Justice Department lawyer and federal judge has cashed a paycheck in his adult life that wasn't issued by the federal government. Nothing in their backgrounds or in their jurisprudence so far indicates that they are about to sign up with either the Sagebrush Rebellion or the Tea Party.
Chief Justice Roberts appears particularly in tune with the exercise of national power. One of his handful of major dissenting opinions came in the 2007 case of Massachusetts v. Environmental Protection Agency, in which the court ordered the federal agency to regulate global warming or give a science-based explanation for its refusal to do so. That case was brought by a group of coastal states, which argued that climate change was lapping at their borders. Chief Justice Roberts objected that the states should not have been accorded standing to pursue their lawsuit. He denounced the "special solicitude" that the court's majority showed the state plaintiffs. An early Roberts dissenting vote, just months into his first term, came in Gonzales v. Oregon, a 6-to-3 decision rejecting the United States attorney general's effort to prevent doctors in Oregon from cooperating with that state's assisted-suicide law.
It's also worth noting that conservative Justice Antonin Scalia did his part to thwart that "federalism revolution" by siding with the majority in 2005's disastrous Gonzales v. Raich, which held that the intrastate cultivation and consumption of marijuana somehow still counted as interstate commerce, resulting in the Court striking down California's popular medical marijuana law. Rehnquist, O'Connor, and Justice Clarence Thomas all dissented in that case, with Thomas presciently remarking, "If Congress can regulate this under the Commerce Clause, then it can regulate virtually anything—and the Federal Government is no longer one of limited and enumerated powers."