To the state in the modern era, the definition it uses is whatever judges, pols, or the voting majority think it is at any one time. Pope Leo XIII warned about the state’s influence concerning marriage 130 years ago. Makes you wonder what the state might consider marriage in another 130 years.
Freegards
Polygamy and child marriages in the 1800’s drove the notion that the state should get involved in issuing “marriage licenses.”
And here we are going full circle in a process that may end up with legalized polygamy.
Just like “guns” get people all emotional demanding new laws today, the polygamists (Mormons in particular) and marriages involving young girls got people emotional back then demanding government intervention.