If Nikolas Cruz was receiving SSDI payments, I wonder if he used those proceeds to purchase his AR-15?

After Mr. Trump focused on mental health in his national address on Thursday in response to the Parkland shooting, many journalists, activists and others, like Mr. Kimmel, noted the repeal of a rule that would have prevented “seriously mentally ill” people from purchasing guns.

Federal law already bars anyone who “has been adjudicated as a mental defective or has been committed to any mental institution” from purchasing a gun. And a majority of states have laws requiring them to report mental health information to the national background check system. But gaps in the system still exist.

After the Newtown shooting, President Obama proposed adding another data source to the background check system: reports from the Social Security Administration of people who receive disability benefits through a third party because of mental impairments. According to a 2016 White House fact sheet, the rule would have affected 75,000 people.

It was opposed by the National Rifle Association, but also the American Civil Liberties Union, which said the rule violated civil rights. Some disability rights groups also argued against the rule on the basis that it perpetuated stigmas about mental illness.

Mr. Trump signed a congressional resolution that expressed disapproval of the proposed rule in February 2017, nine months before compliance would have been required.