Why the Supreme Court decided a 100-year-old gun law was unconstitutional

The Supreme Court issued a decision striking down a more than 100 year old New York state law dealing with who could get a permit to carry a gun in public. This has huge implications, not just in New York. What does the ruling mean? Why did the court just now decide to strike down the law, more than a century later? We asked these questions to Dr. Susan Liebell, Professor of Political Science at Saint Joseph's University.