As to why anyone should care about this, the best articulation Ive seen can be found in this document, whose signatories include Hadley Arkes, J. Budzizewski, James Ceaser, Jean Bethke Elshtain, David F. Forte, Elizabeth Fox-Genovese, Robert P. George, Mary Ann Glendon, Leon Kass, Peter Lawler, David Novak, Marvin Olasky, Jeremy Rabkin, James Stoner, and Christopher Wolfe, to name just a few.
A sample, taken from the executive summary:
We affirm the following ten principles that summarize the value of marriage- a choice that most people want to make, and that society should endorse and support.
Ten Principles on Marriage and the Public Good
Marriage is a personal union, intended for the whole of life, of husband and wife.
Marriage is a profound human good, elevating and perfecting our social and sexual nature.
Ordinarily, both men and women who marry are better off as a result.
Marriage protects and promotes the wellbeing of children.
Marriage sustains civil society and promotes the common good.
Marriage is a wealth-creating institution, increasing human and social capital.
When marriage weakens, the equality gap widens, as children suffer from the disadvantages of growing up in homes without committed mothers and fathers.
A functioning marriage culture serves to protect political liberty and foster limited government.
The laws that govern marriage matter significantly.
"Civil marriage" and "religious marriage" cannot be rigidly or completely divorced from one another.
This understanding of marriage is not narrowly religious, but the cross-cultural fruit of broad human experience and reflection, and supported by considerable social science evidence. But a marriage culture cannot flourish in a society whose primary institutions-universities, courts, legislatures, religions-not only fail to defend marriage but actually undermine it both conceptually and in practice.
Read the whole thing.