It's not just a Jeep SUV.

George Will -- on the role the Court will play in the healthcare debate -- mirrors the role the courts should play in affirming the equality of gay persons under the U.S. Constitution: the protection of individual liberty.

More truly conservative conservatives take their bearings from the proposition that government's primary purpose is not to organize the fulfillment of majority preferences but to protect pre-existing rights of the individual -- basically, liberty. These conservatives favor judicial activism understood as unflinching performance of the courts' role in that protection.

That role includes disapproving congressional encroachments on liberty that are not exercises of enumerated powers. This obligatory engagement with the Constitution's text and logic supersedes any obligation to be deferential toward the actions of government merely because they reflect popular sovereignty.

The latter kind of conservatives are more truly conservative than the former kind because they have stronger principles for resisting the conscription of individuals, at a cost of diminished liberty, into government's collective projects. So a constitutional challenge to the mandate serves two purposes: It defies a pernicious idea and clarifies conservatism.