There’s also a broader issue at work here: the idea of a federal government whose powers are few and defined, limited to that which is specifically enumerated in the Constitution. There have been differences of constitutional interpretation from the beginning of the Republic, as well as disagreements between those who favored a more or less active central government.
But many of those who sneer at the Obamacare lawsuits want to treat this reading of the Constitution as a recent phenomenon, a product of obscure books by right-wing Mormons from the early ’80s or something being peddled on Glenn Beck’s TV show. In fact, this was for much of our history a widely agreed upon understanding of the Constitution. It is the notion that the interstate commerce and general welfare clauses confer sweeping, undefined powers upon the federal government that is of relatively recent vintage.
Conservatives have remained nominally committed to the older understanding of the Constitution, but in practice the mainstream right has only occasionally made constitutional arguments on non-judicial issues. It was much less common to hear objections that Hillarycare was unconstitutional, even though such an argument could clearly be made. Barry Goldwater was the last strict constitutionalist the Republicans nominated for president. Bob Dole was the last to even regularly use constitutionalist rhetoric. To hear so many mainstream Republicans and conservatives arguing that a major new government program is unconstitutional is a breakthrough.
But the new “living Constitution” that mandates liberal policy results on issues ranging from marriage to abortion yet doesn’t meaningfully prevent the federal government from regulating wholly intrastate commerce has been around for over 70 years now. Many large government programs with sizeable constituencies have sprung up under this new reading. These facts are being used to marginalize the older understanding of the Constitution by raising the implication that much of what the federal government currently does is unconstitutional (some liberals like to pretend that this encourages right-wing terrorism). In short, this is a debate over whether the old constitutional doctrines of enumerated powers are still in force or whether traditional constitutionalism should be treated as a fringe position.