from http://www.parlouisiana.org/s3web/1002087/docs/2012_guide_to_constitutional_amendments.pdf
Under strict scrutiny, a law must pass three tests to be considered valid. The government first must prove it has a compelling interest that justifies the passage of the law. In the case of gun laws, public safety is the state’s compelling interest. Courts generally agree that public safety is a compelling interest or a valid reason for states to pass laws that might infringe on an individual’s Second Amendment rights.
The law also must be narrowly tailored to achieve the compelling interest. That is, the law may not be overly broad in its reach. For example, a law that bans any individual with a misdemeanor conviction from purchasing a gun for the rest of his life would be considered excessively broad as compared to a similar ban for an individual convicted of a violent crime.
Finally, the law must also be the least restrictive means of achieving the state’s compelling interest. If there is any alternative that is less restrictive but would still achieve the compelling interest then the law must be judged invalid and overturned.