UNITED NATIONS (AP) — Elected on the nationalist slogan “America first,” President Donald Trump will use his debut address to the U.N. General Assembly to argue that individual nations should act in their own self-interest, yet rally together when faced with a common threat such as North Korea.

Trump, who has warned of “fire and fury” if North Korea does not back down, was expected to argue Tuesday that the dangers posed by Kim Jung Un’s pursuit of a nuclear weapons program should unite all nations. And he planned to issue not just warnings to North Korea but also rebukes to states that have enabled Pyongyang, though it was unclear if he would criticize China by name

Addressing the General Assembly is a milestone moment for any president, but one particularly significant for Trump, a relative newcomer to foreign policy who has at times rattled the international community with his unpredictability. He has pulled the Unites States out of multinational agreements, considered shrinking the U.S. military footprint in the world and deployed bombastic language on North Korea that has been criticized by other world leaders.

Trump frequently belittled the U.N. as a candidate and some within his White House believe the U.N acts as a global bureaucracy that infringes on the sovereignty of individual countries. But the president was expected to stand before world leaders and a global audience and declare that U.N. members, acting as a collection of self-interested nations, should unite to confront global dangers, according to aides previewing his speech.

Beyond North Korea, crisis points the Republican president planned to address include Iran’s nuclear agenda, the instability in Venezuela and the fight against terrorism in Syria and elsewhere.

World leaders, many of whom will be seeing Trump in person for the first time, are bound to take the measure of the man and parse his every word for clues on how he views the U.S. role in the world and within the U.N.

“It’s a tremendous opportunity because the world wants to work with the United States if there’s any way to do so,” said Jon Alterman of the Center for Strategic and International Studies. “He has an opportunity to show surprising openness.”

Trump tipped his hand Monday as he riffed on his campaign slogan when asked to preview his central message to the General Assembly: “I think the main message is ‘make the United Nations great’ — not ‘again.’ ‘Make the United Nations great.’”