The system was developed as a means of national communication to prevent the unauthorized purchased of a firearm or explosive by a known criminal or a serious risk to society. Before the development of the National Instant Criminal Background Check System there was a high risk that those on the denial risk could cross state lines and make a purchase when denied a firearm in their home state. Having instant access to a national database has kept firearms and explosives away from those who most likely intend to do great harm with them.
There are recourses available for those who fail to pass the National Instant Background Check, although few cases have been won. There is a specific criterion for inclusion on the list and that criterion is quite black and white. For instance, if you have plead guilty or no contest to a criminal act even if in fact you were not actually culpable for the act, your name would still end up on the denial list. You simply fit the criteria that the federal government has set in place. No contest pleas are not an admission of guilt but are a consenting agreement that the prosecution has enough evidence to discourage your chances with a jury. Whether or not you are actually guilty of committing the criminal act has no bearing on the fact that your name will be added to the National Instant Criminal Background Check System and you will be denied the purchase of a firearm.
There is nothing unconstitutional about the National Instant Criminal Background Check System (NICS) despite numerous attempts to claim that it is. In the United States, people maintain the right to bear arms until they perform an action that causes the government to believe that they might be a danger to society should they receive a firearm. Being arrested for the failure to pay a parking ticket is huge annoyance, but will not land you on the NISC list. Rather, being arrested for fleeing to avoid apprehension just very well might if you are armed or you put others in danger during the pursuit.
The government does a short review of criminal and mental health cases in order to determine the correct candidates for the denial list for the National Instant Criminal Background Check. This short review includes evaluation of the accused criminal act or mental health diagnosis and a brief review of the final outcome. It does not involve an in depth study of the facts of the case.