Should the white Conservative Christian who shot up Planned Parenthood make us ban Christians from getting guns at gun shows?

Also, gun shows are not the problem. It is no incentive for private party sales to be subject to federal background checks, which examine criminal records and involuntary commitment (mental health and substance abuse) records. All of those records are only created after due process, so are not denying any citizen a right without due process of law.

I think private parties who sell at gun shows, or sell more than a certain number firearms a year, should be required to run background checks like professional sellers.

I think private citizens and responsible gun owners should advocate for a system that allows a private party transfer to be subject to a federal background check done at either a current FFL (pawn shop, gun store owner, booth at a gun show) or the county clerk's office for a reasonable fee, and in exchange the seller will not have any liability for any criminal act committed with that gun, or at least a presumption of innocence that has to be rebutted with evidence of criminal conspiracy.

And a clarification that such immunity or presumption of innocence doesn't create any liability not already existing in law, of course.