There are only two types of nations...those that failed and those that haven't (yet). All things end.
And does that mean the rest of us should be in an almighty rush to let you dipshits flush THIS nation down the toilet, just because YOU have determined that it's going anyway, so it's not worth preserving as long as possible?
What evidence is there that same sex marriages cause nations to fail?
There's same sex marriages in Canada and throughout Europe and they haven't caused the nations to fail.
They don't cause civilizations to fail, normalization of same sex relationships are symptomatic of a civilization that is already failing. Europe is well on its way to failure, Canada and the US not far behind. Out of all of the cultures that have normalized homosexual behavior throughout history and there have been many, not a single one passed that value on to a successor. All successors started out by taking the degraded and subjegated culture and eliminating the acceptance of homosexuality, almost as a first thing.
Certainly in Europe, islam is in the ascendancy. As Russia claws its way back to relevancy as a world player, they too are eliminating the cultural acceptance of homosexuality. Although China has legalized same sex marriage, it is still not accepted and no one has to recognize it. Yet, historically dynastic China was quite open to homosexualty. As a cultural value, it was not passed on.
Something happens to cultures and civilizations that normalize homosexuality. They start dying and continue to die until something comes in to stop it, like Mao's cultural revolution, or overcome by force the way Europe is falling to islam.