Just last year, the Parents Opposed to Pot lobby group tried to sound the alarm on the link between marijuana and mass shootings, compiling a list of mass killers it claims were heavy users of marijuana from a young age, from Aurora, Colo., shooter James Holmes and Tucson, Ariz., shooter Jared Loughner to Chattanooga, Tenn., shooter Mohammad Abdulazeez.

Until we understand those links, it is nuts to enact lax laws that ­encourage more young people to use a drug proven to trigger mental illness.