The United States had a ban on assault weapons from 1994-2004. After 2004, those previously illegal assault weapons could be purchased in stores and were used in multiple mass shootings at concerts, schools and grocery stores. In fact, the shooter this week in Boulder, Colorado, purchased his gun just days after assault weapons were re-legalized in Boulder County.
The federal government does not require background checks for all gun sales. For example, at gun shows or in other private sales, people can legally purchase guns without undergoing a background check.
Even if background checks do occur, certain loopholes can allow people with violent histories to purchase guns, including domestic abusers and stalkers.
The Supreme Court has the power to interpret the Bill of Rights, including how far certain rights extend. For example, the First Amendment’s protection of freedom of speech does not protect violent hate speech. It is not within the government’s power to ban guns because of the Second Amendment; however, it is perfectly lawful for the U.S. government to tighten gun rights to the extent that the Supreme Court sees fit.
Many laws require classes, tests and licenses in order to drive a car, operate machinery, open a restaurant or participate in other activities that may pose a threat to public safety. Laws also require sobriety when operating cars or other machinery. However, federal laws do not require classes, tests, licenses or sobriety for purchasing or using a gun.