Japan on Tuesday unveiled its biggest overhaul of defense export rules in decades, scrapping restrictions on overseas arms sales and opening the way ?for exports of warships, missiles and other weapons. The move aimed at strengthening Japan's defense industrial base marks another step away from pacifist restraints that have shaped its postwar security policy. Wars in Ukraine and the Middle East are ?also straining U.S. weapons production, expanding opportunities for Japan. At the same ?time, U.S. allies in Europe and Asia are looking to diversify suppliers ?as Washington's long-held ?security commitments look less certain under President Donald Trump. "No single…