Donald Trump needs to show via some policy direction that he cares about effects of gun violence. I am certain he knows the initiative he is clamoring for cannot pass, but he bespeaks as a politician.
When politicians at times make crazy recommendations, it is not necessarily the case that they have lost it or are stupid, it simply is the case they need to show they care, but have run out of good ideas. Naturally, an outright ban on guns does not lie within the set of policy initiatives available to most Republicans.
Trump’s idea of arming teachers falls in the same category as Hillary’s idea of free college education.