With a nod to mass shootings in Newtown, Conn., and Aurora, Colo., a federal judge has upheld a suburb’s ban on assault weapons and large-capacity ammunition clips as a proper exercise of public safety. In a 21-page ruling handed down Thursday, U.S. District Judge John W. Darrah cited the banned weapons’ military origins, saying they could be legally restricted by the city of Highland Park because of their “decidedly offensive purpose.” The decision is the latest in a burgeoning Second …