WASHINGTON: Republican White House hopeful Donald Trump promised Wednesday a top-to-bottom overhaul of US foreign policy to put “America First” and make its allies pay up. In a speech short on specifics that left Washington policy experts scratching their heads, Trump warned that Europe and Asia may have to defend themselves. He vowed to tear up trade deals, re-tool NATO to oppose migration and “radical Islam” and put US national interests ahead of all other considerations. “ ‘America First’ will be the major and overriding theme of my administration,” he said, co-opting the slogan of America’s pre-World War II isolationists. The speech had been billed to give Trump, the clear frontrunner for the Republican nomination, a chance to win over a skeptical foreign policy establishment. But many were quick to point out the contradictions in a strategy of restoring US strength and crushing the Islamic State group while cutting allies loose.