President Donald Trump’s “America First” rhetoric and confrontational negotiating style have sparked frantic calls to the White House and Congress from diplomats and lobbyists concerned that the United States no longer has their back. When word swirled through Washington on Thursday that Trump might be preparing to ease U.S. sanctions on Russia, worried European diplomats began calling the National Security Council and asking if the rumors were true, said a former U.S. official familiar with the situation.