What can Machine Learning Tell Us About America's Gun Laws?

In the United States, it seems we never have to go more than a few weeks without hearing about another mass shooting. With each new incident comes renewed calls to strengthen gun control laws, expand federal background checks, and get rid of assault rifles. Though the opposing faction promptly dismisses each appeal by citing 2nd Amendment rights, other discussions of practicality often emerge. Specifically, the efficacy of such laws is often called into question. How do we know which laws work and which ones don't?