President Donald Trump returned to the United Nations on Tuesday to boast of his second-term foreign policy achievements and lash out at the world body as a feckless institution, while warning Europe it would be ruined if it doesn’t turn away from a “double-tailed monster” of ill-conceived migration and green energy policies. Later, in a bilateral meeting with U.N. Secretary General Antonio Guterres, Trump’s tone toward the United Nations shifted after his speech earlier in the day blasted the world body for issuing “empty words.”