MACAO -- China's decision in 2002 to open Macao's gambling business to outside competition has been good for Sheldon Adelson, a friend and staunch supporter of Donald Trump, the former casino owner who occupies the White House.

Moving target: U.S. casino operators, who take more than half of Macao's casino revenues, may be at risk of trade war backlash. (Photo by Manda Yeung)
Trump ally Adelson among Americans seeking fresh government licenses