The gov. has an interest in DESTROYING traditional marriage. They want to destroy the family and make everyone dependent on the gov.
By not defending traditional marriage laws, an illegitimate government will do just that, as shown in the previously attached article by Don Feder:
"After the courts delivered a series of body-blows to marriage over the past four decades -- with no-fault divorce, abortion, the de facto legalization of pornography and legitimizing cohabitation -- the justices thought: Oh, what the hell, what harm can there possibly be in opening the honorable estate to members of the North American Man/Boy Love Association and Dykes on Bikes?"