Sean Wilentz at The New Republic has a better explanation of the nullification nonsense this morning than I had yesterday:
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.
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.
The whole idea is childish in a way. Little children and extremist politicians have a definition of "fair" that only encompasses what they want. Seriously, doesn't this whole thing look like a temper tantrum? When you start to think about the far right as a bunch of little kids more concerned with winning than governing, their whole ethos becomes clearer.
In other words, my message to Western legislatures is: Grow the hell up. We have real problems that need real solutions. Act like adults and get back to work.