The Supreme Court on Wednesday upheld Biden-era federal regulations on “ghost guns,” mail-order kits that allow people to build untraceable weapons at home – handing gun control groups a rare win at the conservative high court. Justice Neil Gorsuch wrote the opinion for a 7-2 majority that included both liberal and conservative justices in one of the most closely watched Supreme Court cases of the year. “Perhaps a half hour of work is required before anyone can fire a shot,” Gorsuch wrote. “But even as sold, the kit comes with all necessary components, and its intended function as instrument of...