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.

His roughly hour-long speech was both grievance-filled and self-congratulatory as he used the platform to praise himself and lament that some of his fellow world leaders' countries were “going to hell.”

The address was also just the latest reminder for U.S. allies and foes that the United States — after a four-year interim under the more internationalist President Joe Biden — has returned to the unapologetically “America First” posture under Trump.

“What is the purpose of the United Nations?” Trump said. “The U.N. has such tremendous potential. I’ve always said it. It has such tremendous, tremendous potential. But it’s not even coming close to living up to that potential.”

World leaders listened closely to his remarks at the U.N. General Assembly as Trump has already moved quickly to diminish U.S. support for the world body in his first eight months in office. Even in his first term, he was no fan of the flavor of multilateralism that the United Nations espouses.

Trump touted his administration's policies allowing for expanded drilling for oil and natural gas in the United States, and aggressively cracking down on illegal immigration, implicitly suggesting more countries should follow suit.

He sharply warned that European nations that have more welcoming migration policies and commit to expensive energy projects aimed at reducing their carbon footprint were causing irreparable harm to their economies and cultures.

“I’m telling you that if you don’t get away from the ‘green energy’ scam, your country is going to fail," Trump said. "If you don’t stop people that you’ve never seen before that you have nothing in common with your country is going to fail.”

Trump added, “I love the people of Europe, and I hate to see it being devastated by energy and immigration. This double-tailed monster destroys everything in its wake, and they cannot let that happen any longer.”

The passage of the wide-ranging address elicited some groans and uncomfortable laughter from delegates.