Trump stuns with call to resume nuclear tests — why now, and what it could mean

President Donald Trump’s announcement that the U.S. would revive nuclear weapons testing — which the U.S. has not done since 1992 — left experts, lawmakers and military personnel scratching their heads Thursday.The president announced, just before his high-stakes meeting with Chinese President Xi Jinping, he is instructing the Pentagon to start testing nuclear weapons on an "equal basis" as Russia and China, and that the process for testing these weapons would begin immediately.  "They seem to all be nuclear testing," Trump later told reporters on Air Force One. "We don’t do testing — we halte