During a lengthy speech Monday about possible policy changes in the wake of the latest deadly school shooting, President Donald Trump suggested placing people who show signs of violent behavior into mental institutions.

“You know, in the old days we had mental institutions. We had a lot of them. And you could nab somebody like this,” Trump said at a meeting with governors. “But you used to be able to bring them into a mental institution and hopefully he gets help or whatever. But he’s off the streets. You can’t arrest him, I guess, because he hasn’t done anything, but you know he’s like a boiler ready to explode, right?”

Trump did not explicitly call for the government to fund mental institutions for those who appear poised to commit mass atrocities, but he suggested that lawmakers begin discussing mental institutions.

“We’re going to have to start talking about mental institutions, because a lot of folks in this room closed their mental institutions also. So we have no halfway. We have nothing between a prison and leaving him at his house, which we can’t do anymore. So I think you folks have to start thinking about that,” he told governors.