President Barack Obama said Donald Trump’s suggestion that Japan and South Korea should consider obtaining nuclear weapons demonstrates the Republican presidential front-runner’s lack of understanding about foreign policy and the world at large, at the close of a two-day summit on nuclear security.Speaking to reporters at the Nuclear Security Summit, Obama said that Trump’s willingness to undermine decades of international security policy and efforts towards nuclear disarmament rendered him unqualified for the presidency. “We don’t want somebody in the Oval Office who doesn’t recognize how important that is,” Obama said.Trump made these remarks to CNN’s Anderson Cooper during a town hall in Wisconsin, and he also floated the possibility of using nuclear weapons in a military conflict in Europe, saying, “You don’t want to, say, take everything off the table.” “The person who made the statements doesn’t know much about foreign policy or nuclear policy or the Korean Peninsula or the world generally,” Obama said.Obama described the U.S. nuclear umbrella for Japan and South Korea, in place of their own arsenals, as “one of the cornerstones of our presence in the Asia Pacific,” which has provided the U.S. peace, prosperity and flowing commerce.”It has prevented the possibilities of a nuclear escalation and conflict,” he added. “You don’t mess with that. It’s an investment that rests on the sacrifices that our men and women made” in World War II. He concluded, “We don’t want someone in the Oval Office who doesn’t recognize how important that is.” The summit came as the Republican front-runner to replace Obama in the White House made several controversial nuclear proposals this week. Barack Obama has given his most damning criticism of Donald Trump so far, claiming the presidential hopeful ‘doesn’t know much about the world’. Obama has made no secret of his disdain for the Republican front-runner but he condemned his latest comments in scathing fashion.