The author is wrong. The greatest threat to the institution of marriage is from redefining the word marriage. There is no rational basis for excluding poly____ marriages or marriages of convenience if the meaning is liberalised to include those of the same sex entering into marriage. The inevitable result is the dissolution of the institution of marriage which I find to be a bad outcome.
That is where reform is most urgently needed and it requires no constitutional amendments.
Reform of marriage and the redfining of marriage are not mutually inclusive. Marriage law can be reformed while maintaing the meaning of the word.