Paris (AFP) - US Republican presidential frontrunner Donald Trump has rung alarm bells around the world with his proclamations on foreign policy, but his targets are increasingly shrugging off his barbs. By suggesting that NATO is "obsolete" and that Japan and South Korea should acquire nuclear weapons to rid the United States of the burden of protecting those countries, Trump has called into question some of the cornerstones of US foreign policy for decades. The property developer's comments have earned sharp rebukes from President Barack Obama and Secretary of State John Kerry. An exasperated Obama said he was "getting questions...