Regulation. Active attempts at reducing the gun load. Anything more than fucking "thoughts and prayers" when all y'all get another batch of children butchered in school.
Here's a start: licensure. Freedom of movement is part of the American constitution as well, yet you license cars, have proof of insurance, etc. Driving without a license or insurance gets you into hot water.
Now try the same with guns. With commensurately higher penalties if caught owning and using without a license. This would be literally the minimum you could do ... and you don't do even that much.
But hey, congrats on the "thoughts and prayers". I'm sure they'll protect you from the next insane fuckwit in a school.