This post by Lawrence Lessig addresses the issue of the executive’s responsibility to judge constitutionality in enforcing the law as it relates to the current events in San Francisco, where many gay people are getting married in defiance of state law.

Quoting Lessig:

Presidents’ Day lesson: the mayor’s duty

The Mayor of San Francisco has decided that a state law is unconstitutional under the state constitution, and has therefore ordered city clerks to disobey the law and obey the constitution. This troubles my friend Dan Gillmor, who on last count was right about everything else. And it is an action by a mayor, who on last count was wrong about a bunch of very important things. So who’s right now? I try to answer that in the extended essay that follows.

This turns out to be more complicated than at first it seems. And there may be something peculiar about California state law that I don’t understand (and would be grateful if someone would correct me). But the answer does not turn upon the rightness or wrongness of gay marriage (I, like Gillmor, believe the state has no legitimate reason to deny gay and lesbian couples the right to affirm a commitment to each other as strong and powerful as anyone else). It turns instead upon your view of the role of an executive.

Full article: http://www.lessig.org/blog/archives/001739.shtml