President Donald Trump said on Thursday he wants to ensure the U.S. nuclear arsenal is at the "top of the pack," saying the United States has fallen behind in its weapons capacity. In a Reuters interview, Trump also said China could solve the national security challenge posed by North Korea "very easily if they want to," ratcheting up pressure on Beijing to exert more influence to rein in Pyongyang's increasingly bellicose actions. Trump also expressed support for the European Union as a governing body, saying "I'm totally in favor of it," and for the first time as president expressed a...