A little while back the State of New Jersey was considering a law that would ban all marriages under the age of 18. This is a trend in the USA, meant to protect underage women from being taken advantage of. Last year the governor decided to not sign the new law because it did not include an exception for religious reasons, or with parental consent. The governor of New Jersey has now decided to sign on the law, with no exceptions. It is now illegal in new Jersey to get married under the age of 18. Full Stop. No exceptions.
sources: Hamodia, Behadrei, Washington Post

Considering that so far only two states have adopted this law with no exceptions, the solution it seems, for people wanting to marry under 18, will be to go to a nearby state, such as New York or Pennsylvania... though they are the closest states to NJ - I do not include Delaware as that is the other state banning such marriages with no exceptions - it is still a far drive and would be difficult for many to make weddings so far away and to expect guests to participate.. 

I expect the local and national Orthodox Jewish, and probably some Christian and Muslim, organizations to lobby hard to get some religious exception added to the law.