Marriage is not covered by the constitution, therefore it is left to the states. I agree with Perry on the issue, it is a states issue. Me personally, I could care less who marries who, but not at the expense of our constitution and how it was intended to be enforced.
Gay marriage is being used by the left as a vehicle for future agendas. If they can circumvent the constitution through gay marriage, they will surely circumvent it for other purposes. The sad thing is that gay people cannot see they are being used by the left in the way that they are.
Don't you answer yourself in the first two lines of your post? You acknowledge same sex marriage isn't mentioned in our constitution. And, I'm assuming you understand that things not mentioned in the constitution are not to be tried on a constitutional basis but a civil basis. So, the constitution is moot in your argument.
That begs the question: what political agenda? Since there's neither threat nor challenge to the constitution, how are these mysterious and, in your opinion no doubt, nefarious ways "the left" circumventing the constitution?
You see the Gay community being used as pawns and dupes, yet the Gay community has successfully lobbied for first class citizen status rather than the second class status imposed upon them by a repressive, chastity-driven, bigoted minority of the pseudo-righteous.
No one thinks legislating morality is a wise move.