President Biden used his fourth and final address to the United Nations General Assembly today to argue that “things can get better,” even in a world that appears enveloped in crises. He celebrated his efforts to defend Ukraine and rebuild America’s global alliances, however he also said that the progress could easily collapse if the U.S. turns to isolationism.

“Our task, our test, is to make sure that the forces holding us together are stronger than those that are pulling us apart,” Biden said to the world leaders gathered in New York City. “The choices we make today will determine our future for decades to come.”

The president’s warning appeared to be an unspoken reference to the possible election of Donald Trump, who has repeatedly criticized the NATO alliance. Biden cast his decision to step down from the presidential ticket as a lesson for world leaders. “Some things are more important than staying in power,” he said.

For more: Many leaders focused on the Middle East, with some speakers criticizing Israel for its war with Hamas in Gaza, where a cease-fire has appeared to become less likely in recent weeks.

Ukraine: President Volodymyr Zelensky pleaded for continued support: “Russia can only be forced into peace,” he said.