Proof Please

Huckabee, the up and coming Republican presidential
candidate, recently
gave an interview to GQ where he said

There’s never been a civilization that has rewritten
what marriage and family means and survived.     

  This statement is consistently made by opponents of family
equality as if it’s a proven fact, something that should be as
clear a fact as the sun rising in the East. Yet, not once have I
seen proof or an example of the veracity of this statement.  Show
me the proof. Show me one example of a civilization that
changed their definition of marriage and family and then fell
because of it. In fact, show me one civilization that has not
changed their definition of marriage and family and didn’t
fall.   Is this a necessary factor, but not sufficient? (a
civilization won’t fall if it only changes it’s definition of
family and marriage, other factors are needed including this) Or a
sufficient factor, but not necessary? (this alone will cause a
civilization to fall, but other factors can too). Or is it both
necessary and sufficient? Because I’d like to know.From my reading
of history, and granted I’m not a historian, civilizations have
changed their definition of marriage and family many times, to and
from polygamy, requiring and not requiring licensing, accepting and
not accepting adoption, etc. and they didn’t fall. Many have fallen
(well all) without changing the definition. Can someone please
(Huckabee?) submit the documented  destruction of a civilization
due to family and marriage redefinition? (via DailyKos)  (btw,
I’d like to say thanks to David and Family Equality for allowing me
to co-blog here. I am looking forward to the opportunity)