In my column this week, I looked at the skirmish between Texas Gov. Rick Perry and former Sen. Rick Santorum over whether states should be allowed to legalize gay marriage and marijuana. Due to space constraints, I wrote about the issue in terms of the broader debates about federalism and legislating morality. Yet it’s true, as some readers have indicated, that the marriage issue is a bit more complex. There are obvious practical matters associated with allowing different marriage laws in different states, given that people move from one state to another. Also, it isn’t a matter of banning a specific behavior (such as gay sex), but rather a debate over whether society should put its stamp of approval and confer a special status that up to recently had only been granted to straight couples. Though I ultimately believe in  allowing gays to marry, I recognize that the idea raises different questions than the issue of medicinal marijuana. In that case, it’s a matter of the federal government forbidding an activity, and the legal issues with having different medical marijuana laws in different states aren’t as thorny.