The Centrist Coalition has an interesting debate going on over the recent decision on medical marijuana and the proper reach of the commerce clause. Seems to me the clause was involved in the civil rights era debates over the public accommodations provisions as well as being the prop for some of the New Deal's farm programs--hence I'm content with the status quo.
One way to look at the issue is to focus on the end results, not the process. In a country with a diverse society and a democratic form of government, will justice be better served by making decisions at the national or the state levels? As American history was interpreted when I was in school, decisions at the national level were best, as shown by the filibusters of civil rights legislation, etc. Even today the Republicans have moved from attacking the nationalization of the education system to supporting it--national standards are better than local.
Liberals and libertarians have mixed feelings. Look at the range of social issues:
Prohibition: constitutionally guaranteed local option
Abortion: constitutional by SOCUS national rules
Marijuana: national rules, but lib/libs would prefer local
Gay marriage: local rules and lib/libs would prefer local
Positioning on constitutional issues depends in part on projections of how society is going to change. You could argue in the 1970's that ERA was an expression of lack of confidence in the society. Would women be in a significantly different position today if it had been adopted? I doubt it, but am open to argument. Is opposition to gay marriage going to fade like opposition to women's rights has, or is it going to remain strong like opposition to abortion?
If one takes a "principled" position on constitutional interpretation you may end up 30 years from now in an awkward position.