Why does the US have so many child brides?

[donotpissoffacow]

While countries like Zimbabwe, Malawi and El Salvador have recently banned child marriage, it remains legal in the US - and half of states have no set minimum age below which you cannot get married.
http://www.bbc.com/news/av/world-us-canada-41727495/why-does-the-us-have-so-many-child-brides

This is nothing new. It's been there all along. I can remember a 6th grade classmate who planned to marry as soon as the school year ended...1950s. How about the old joke regarding (name a southern state) and 12 year old virgins? That's not just a mean dig at a neighbor but a recognition of a need to marry them off young. I'm certain there are plenty of such stories.

Want to bet Jeff Sessions would take umbrage if we try to change the age of legal marriage in his imaginary state?