The way the Supreme Court protects individual constitutional rights against encroachment by the government is by weighing the government's interest in a particular law against the individual right preserved in the Constitution.
For example, when the government passes a law censoring people from engaging in core political speech, the court requires the government to demonstrate it has a compelling interest in the censorship and to prove that the measure is the least intrusive means of achieving that governmental interest. If it can't prove both, the law must be struck down.
Not all rights warrant the toughest level of constitutional protection. In the intermediate level, judges often attempt to balance competing interests to reach the proper outcome.
What standard of review do gun-control advocates want?
The Brady Center to Prevent Handgun Violence has filed a friend-of-the-court brief in the Chicago case urging the justices to establish a standard of review in which judges would be reluctant to overturn gun-control regulations enacted by elected officials.
"Gun policy is best determined as it always has been in this country: in the political arena, without courts second-guessing reasoned legislative judgments," writes Paul Wolfson in his brief on behalf of the Brady Center.
What standard of review are gun-rights supporters seeking?
Many argue that the Second Amendment right to keep and bear arms is a fundamental right that can be limited only in the narrowest circumstances and only when the government demonstrates a compelling reason. "We think the Constitution provides the proper test. It is: 'shall not be infringed,' " said Larry Pratt, executive director of Gun Owners of America, quoting from the amendment. "We think 'shall not' means 'none.' "