U.S. authorities have arrested a leader of a Japanese crime syndicate—also known as Yakuza—and three Thai men for drug trafficking and trying to acquire U.S.-made weaponry for “unstable nations,” the Justice Department said Thursday. Yakuza leader Takeshi Ebisawa and his Thai national affiliates, Sompak Rukrasaranee, Somphob Singhasiri, and Suksan Jullanan, were arrested in Manhattan on…