The challenge was brought by gun rights advocates seeking to overturn bans on assault weapons passed by Connecticut and New York after the 2012 killing of 26 people at an elementary school in Newtown, Connecticut.
In that attack, a mentally disturbed man armed with a military-style semi-automatic assault rifle shot to death 20 children and six others at the school.
The Supreme Court's action, while effectively validating the New York and Connecticut laws, was silent on the specifics of the case and why it declined to hear the challenge.
