Up until last year, President Obama publicly purported to support traditional marriage laws in the states while also advocating robust civil unions for same-sex couples. With yesterday’s amicus brief, Obama now maintains that the position that he held until last year is unconstitutional—that a state can’t confer on same-sex couples the legal incidents of marriage without also calling their relationships marriages.

What a stark example of the utter unreliability of the “living Constitution” approach. Given the laughable instability of Obama’s constitutional thinking, why should anyone accord his views any respect?