At  press conference in Tokyo, President Barack Obama said Thursday that the US would come to Japan’s defense if China further threatened a disputed chain of islands. But, he stressed, he was not drawing another “red line” on possible military action. “We have strong relations with China,” Mr. Obama said. “But we have also emphasized … all of us have responsibilities to maintain basic rules of the road and international order. My hope is that China will continue to engage with us.” Obama is on an oft-delayed Asian trip to Japan, South Korea, Malaysia and the Philippines, constantly pursued by the Ukraine crisis.