SCROTUS eliminated a rule, made under Obama, that forbids demented old people from buying guns.

I don't know whether demented people will misuse guns very often, but they often mistake their relatives for burglars. Those who are well enough to grab and shoot a gun could shoot their relatives.

If there is no research on whether those people are likely to misuse guns, why is that? Because Republicans have prohibited federal funding for any research about gun violence. Step 1: ensure there is no research. Step 2: cite the lack of research as a reason to eliminate a rule.