Republicans and other unsavory Tenthers want to use discredited and obsolete arguments to roll back the march of progress. Sean Wilentz in the New Republic:
Now, as in the 1860s and 1960s, nullification and interposition are pseudo-constitutional notions taken up in the face of national defeat in democratic politics. Unable to prevail as a minority and frustrated to the point of despair, its militant advocates abandon the usual tools of democratic politics and redress, take refuge in a psychodrama of “liberty” versus “tyranny,” and declare that, on whatever issue they choose, they are not part of the United States or subject to its laws—that, whenever they say so, the Constitution in fact forms a league, and not a government. Although not currently concerned with racial supremacy, the consequence of their doctrine would uphold an interpretation of the constitutional division of powers that would permit the majority of any state to reinstate racial segregation and inequality up to the point of enslavement, if it so chose.Wilentz is overly generous, I think. The Tenthers would by and large be happy to wake up in the ante bellum South - just so long as they got to be aristocrats and not poor white farmers or, heaven forfend, with their color changed.
That these ideas resurfaced 50 years ago, amid the turmoil of civil rights, was as harebrained as it was hateful. But it was comprehensible if only because interposition and nullification lay at the roots of the Civil War. Today, by contrast, the dismal history of these discredited ideas resides within the memories of all Americans who came of age in the 1950s and 1960s—and ought, on that account, to be part of the living legacy of the rest of the country. Only an astonishing historical amnesia can lend credence to such mendacity.
This is not to say that I think the Democrats' heath insurance reform is a slam dunk to pass Constitutional review. There's ample precedent for mandates to have auto insurance, though some states provide alternatives to purchasing a policy, such as posting of a bond, essentially self-insurance. But this health insurance mandate goes a bit further in that dying and emigrating are the only ways to escape it.
Of course, there's also the current Supreme Court, still dominated as it is by conservatives, four of them accurately hard-right conservatives - Scalia, Thomas, Alito, and Roberts. An ideologically similar court was willing to nullify the outcome of the 2000 Presidential election (or, at the very least, to fix the result before the result could be accurately known). It would be naive to think their judicial modesty - not at all evident on the hard right, by the way - might restrain them from overturning a democratic act of Congress.