I've been in rainy California volunteering against Proposition 8, which would ban gay couples from marrying in the state, and so just now read David's post from yesterday critiquing Barack Obama's views on gay marriage and Prop 8. I do see some (not insoluble) logical problems in Obama's opposition to gay marriage and Prop 8, as I wrote in a post in July, and so to that extent I agree with David.
But as for the consistency of his constitutional views, I tend to think we shouldn't hold politicians to high standards of exactitude when they do interviews on MTV. So let me indulge Obama a bit more than David is inclined to do. Responding to a question about Prop 8, here's what he said:
I think it's unnecessary. . . . I believe marriage is between a man and a woman. I am not in favor of gay marriage. But when you start playing around with constitutions, just to prohibit somebody who cares about another person, it just seems to me that's not what America's about. Usually, our constitutions expand liberties, they don't contract them.
David reads this as a generalizable claim by Obama that constitutions should not be amended to contract liberties previously "expanded," in this case, by the California Supreme Court decision for SSM last May. He then chides Obama for presumed inconsistency in not similarly opposing the contraction of slaveholders "liberty" to own slaves, the right to be free of income taxes, and the economic liberty recognized in Lochner.
As I interpret Obama's statement, however, he is making no such generalizable claim about "expansions" of constitutional "liberty" being irreversible. He's making a general claim that seems to me quite defensible: that most of our constitutional charters and their most important individual rights provisions have expanded or at least consolidated and secured individual liberty.
Obama is asserting a policy preference against gay marriage. (Actually, I don't think he really is against gay marriage but that he's saying so for political reasons, which makes him a politician.) If he were in a legislature he would vote against it. He may see allowing gay couples to marry as an "expansion" of liberty for them, but it's an expansion that he opposes just as he would oppose expansions of other liberties (e.g., to use drugs, to prostitute oneself, and so on). It is possible, especially if you're not a libertarian, to regard something as both a liberty and a bad idea.
But he does not believe we should amend a constitution to prevent the legislature from allowing SSM, and thus expanding liberty at some future date when he and other legislators with more information and experience may change their minds on the subject. And more to the point in the case of California, he does not believe we should reverse their liberty once gay couples do in fact begin marrying, as some 18,000 of them have done since June and as many more thousands would do if allowed.
Obama is probably not agnostic about what counts as a liberty, or as a worthwhile liberty, and so I presume would reject the notion that his opposition to Prop 8 should compel him to support Dred Scott, the end of income taxes, and the demise of minimum wage and maximum hours laws.
Of course, you can disagree with him about the substance on gay marriage, the income tax, slaveholders' "rights," and liberty to contract. But that would require a much more extended discussion than his soundbite response to a question from "Gangstagigz" in San Leandro. At the end of the day Obama might not have very sound reasons for his substantive views on these matters of "liberty," but at least at this point it's not obvious to me that his stand against amending a constitution to prohibit the freedom to marry while tolerating limits on other claimed liberties is "silly."
Finally, I should note one thing for the record. The California marriage decision did not "lead to the movement to pass Prop 8," though it may have added fuel to the fire. The proposition was filed and the requisite number of signatures gathered before the California decision came down. The vote tomorrow on the marriages of gay Californians was going to happen regardless of what the California court did.