The U.S. Supreme Court could have used  the legal challenge to Connecticut's law banning many semiautomatic weapons to firmly establish the constitutionally of such restrictions. While it did not go that far, its decision Monday not to take up the appeal also speaks loudly.

Passed with bipartisan support in the wake of the killing of 20 first graders and six educators at a Newtown elementary school in December 2012, the Connecticut law bans military-style semiautomatic assault weapons and magazines capable of holding more than 10 rounds. As noted by Connecticut Attorney General George Jepsen, the law was a “reasonable, sensible and lawful” response to the massacre.

Last October, the U.S. Court of Appeals for the Second Circuit upheld the constitutionality of the ban almost entirely. By deciding not to hear the appeal of that ruling, the high court let stand the logic behind the appellate court decision.

Last December, the Supreme Court likewise refused to hear an appeal challenging the constitutionality of an ordinance, approved in 2013 by Highland Park, Ill., which also banned semiautomatic assault weapons and large-capacity magazines. A lower appellate court had affirmed the constitutionality of that ordinance, too.

What appears to be at work here is that the U.S. Supreme Court recognizes that the lower courts are getting it right when it comes to interpreting the parameters set by the landmark 2008 District of Columbia v. Heller decision. That ruling struck down a strict Washington, D.C. law that barred keeping guns in the home for self-defense.

Written by the late-Justice Antonin Scalia, Heller established that the Second Amendment protects the right of individuals to possess firearms for self-defense, not just in connection with “a well-regulated Militia.”

But Scalia also noted, “The right secured by the Second Amendment is not unlimited,” pointing to “support in the historical tradition of prohibiting the carrying of dangerous and unusual weapons."

In leaving in place these laws, the Supreme Court is giving state and local elected leaders substantial leeway in defining prohibited dangerous and unusual weapons.

That is good news for gun-reform advocates.