There is a lot that needs to be done to overhaul the US gun laws to have legislation consistent with the United States Constitution, traditions, and values. However, the current process for background checks includes a loophole such that approximately 40% of gun sales do not go through the background checks.
This loophole, commonly known as the gun show loophole because it is most frequently used there, allows for sales of firearms with no background check. This means that individuals with mental health records that would prevent purchasing, criminals, drug abusers, domestic violence offenders, people with restraining orders, and others who shouldn't legally be able to purchase a firearm can bypass the background checks.
This is a quick step that the country would agree with doing.