Advocates of gun rights and opponents of gun violence are demonstrating outside the Supreme Court as justice begin hearing arguments over the meaning of the Second Amendment's "right to keep and bear arms."

Dozens of protesters waved signs as they mingled with tourists and several people waited in long lines to get into the courtroom but were turned away. More than 50 people stood in line overnight for a coveted seat in the courtroom. The line began forming on Sunday.

Demonstrators included members of the Brady Campaign to Prevent Gun Violence, Second Amendment Sisters and Maryland Shall Issue.Org, a group that wants to make it easier to buy guns.

The basic issue before the justices is whether the amendment protects an individual's right to own guns or whether that right is somehow tied to service in a state militia.