Alito was also part of the 5-4 majority in the 2008 case of District of Columbia v. Heller that struck down a gun ban in Washington. That was the first time the court ruled that the Second Amendment right to bear arms extended to individuals, not just formal militias, but that decision applied only to federal laws.
A lower court must still invalidate the 1982 Chicago law, a step the Supreme Court ruling makes all but certain.
Writing in dissent Monday, Justice Stephen G. Breyer - joined by Justices John Paul Stevens, Ruth Bader Ginsburg, and Sonia Sotomayor - noted that handguns cause an estimated 60,000 deaths and injuries each year. Breyer cautioned that the ruling would hinder state and local efforts to control the carnage.
"Unlike other forms of substantive liberty, the carrying of arms for that purpose often puts others' lives at risk," Breyer warned.
Alito's 45-page majority opinion, issued on the last day of the court's 2009-10 term, built directly on the Heller decision and emphasized throughout the traditional deference that courts and legislatures have paid to gun ownership. Alito was joined in the majority by Chief Justice John G. Roberts Jr. and Justices Antonin Scalia, Anthony M. Kennedy, and Clarence Thomas.
"King George III's attempt to disarm the colonists in the 1760s and 1770s provoked polemical reactions by Americans invoking their rights as Englishmen to keep arms," Alito wrote.
He added that for the authors of the Bill of Rights, which includes the Second Amendment, "the right to keep and bear arms was considered no less fundamental."
