Last year I cited Indiana's old universal background check statute which was repealed in 1998.
I have asked for:
1. 1 crime that was prevented by Indiana's UBC.
2. 1 prosecution under a violation of Indiana's UBC.
I STILL await those examples.
In theory, in order for a universal background to be effective, it needs to be universal. If a state has a UBC, and yet the surrounding states don't, then given the ease of movement between those particular states, a UBC would be ineffective. For instance, I'm from a dry county in Alabama, but all the other counties surrounding were wet. And for all they did to stamp out alcohol, we were swimming in booze.