Rubio has an “A+” rating from the National Rifle Association, and voted for numerous bills expanding gun rights, including Stand Your Ground, when he served in the Florida Legislature. And the degree to which he would give ground to gun-control supporters remains far from clear after the slaughter of 17 people last Wednesday afternoon at Marjory Stoneman Douglas High School in Parkland, a Fort Lauderdale suburb.

Still, Rubio also indicated a willingness to expand background checks; consider a “gun-violence restraining order” to remove weapons from those accused of domestic violence; examine banning so-called “bump fire” conversion kits that enable semi-automatic rifles to fire like machine guns; and improve violence-prevention programs, pioneered in Los Angeles, to detect signs of trouble ahead of time.

“If you’re going to talk about gun violence, you’re going to have to focus on the gun part. But you also have to focus on the violence part,” Rubio told POLITICO. “What is the catalyst causing people to do this?”