The 80th General Assembly at the United Nations, which concluded on Sept. 29, had its customary share of tense moments and more than the usual number of plain odd ones. Diplomats stormed out of Israeli Prime Minister Benjamin Netanyahu’s speech in protest of the Israeli military campaign in Gaza. France, Britain, Australia and Canada joined 153 other U.N. member nations that had previously recognized Palestine as a state.

And U.S. President Donald Trump had run-ins with an escalator and a teleprompter that spawned new MAGA conspiracy theories and led a Fox News host to (jokingly?) call for a U.S. bombing run over the East River headquarters of the world’s governing body.

During his address to the General Assembly, which continued well past its allotted time, Mr. Trump offered a meandering critique of the institution, chest-beated America’s hotness and deplored what he saw as the crummy economic and social conditions of other states around the world.

The president added his voice to a growing chorus on the U.S. right that consistently condemns the U.N. agenda, even its existence. Many Republicans now openly call for the United States to withdraw from the United Nations, an exit that would no doubt begin a League of Nations-style institutional meltdown. According to a Gallup poll released in September, 36 percent of Republicans favor U.S. withdrawal from the United Nations, nearly double the 19 percent who held that view in 2005.

Those U.S. critics were accompanied by new voices from within the United Nations itself, urging not a U.S. expulsion, exactly, but the movement of U.N. headquarters from New York. The Trump administration’s unpredictability on visas has convinced some that the United Nations needs to move to a truly neutral corner if it is going to be able to fulfill its commitment to unfettered international dialogue.

Trump’s U.N. pull back

The Trump White House refused to OK travel by representatives from the Palestinian Authority to participate in this General Assembly, where a cease-fire in Gaza and the future of Palestine were at the forefront of discussion. Palestinian President Mahmoud Abbas was forced to address the United Nations via an internet simulcast.

U.S. officials also revoked the visa of the president of Colombia, Gustavo Petro, after he used his time at the General Assembly podium to criticize U.S. policy in Gaza and U.S. missile strikes in the Caribbean. He later joined a protest outside the United Nation that was calling for Palestinian statehood, where he suggested U.S. soldiers should refuse to follow Mr. Trump’s orders and “not point their guns at people.”

The United States has already begun a retreat from multilateral organizations housed at the United Nations, withdrawing this year from the Paris climate agreement, the World Health Organization, the U.N. human rights office and Unesco. It has refused to continue funding for the U.N. body in charge of humanitarian relief in Gaza and the West Bank and has not paid its total U.N. dues this year at all, adding to a $2.4 billion shortfall in operational funding and a $2.7 billion shortfall in peacekeeping that is crippling global initiatives.

The United States, one of the international body’s founding members, has traditionally been its largest donor state, responsible for about 25 percent of its budget. It has not yet turned over its $1.5 billion 2025 assessment, and it is not clear if the Trump administration plans to make the 2025 payment or to sign the check on future annual assessments.

Should the Trump administration follow through on threats to pull out altogether, it is hard to imagine how the United Nations can proceed in its current form or mount a meaningful humanitarian effort in global hot spots like Sudan, Afghanistan and Haiti.

U.N. Secretary General António Guterres said aid cuts are “wreaking havoc,” calling them “a death sentence for many.” A U.N. appeal for $44 billion to help 114 million people around the world is currently only 19 percent funded.

Despite the growing American estrangement and threats to withdraw, Vatican officials still perceive the United Nations as a fundamental instrument of world peace and justice seeking.

Archbishop Paul R. Gallagher, the Holy See secretary for relations with states and international organizations, spoke at the General Assembly on Sept. 29, offering a vote of confidence and extending the church’s support for multilateral actors and international dialogue. The 80th anniversary of the founding of the United Nations, he said, provides an “opportune moment to reaffirm the organization’s core values of fostering international peace, development and universal human rights—values that are all the more important in an increasingly fragmented world.”

In what was perhaps a note to the Trump administration, he added: “It is important to remember that isolationism leads to unpredictable instability, whereas unity fosters responsible resilience and shared progress. This is strikingly evident in the current circumstances, where escalating geopolitical tensions, a raging climate crisis, widening inequalities and rising poverty demand renewed global solidarity.”

The archbishop warned of “emerging threats such as environmental degradation and technological disruption, which no single country can tackle alone.”

Quoting Pope Leo XIV, he said, in perhaps another rebuke to the United States in the wake of its drone strikes across the Caribbean and to Israel as it continues a merciless campaign across Gaza, “It is troubling to see that the force of international law and humanitarian law seems no longer to be binding, replaced by the alleged right of the stronger to impose themselves without limits.”

“This is unworthy of our humanity, shameful for all mankind and for the leaders of nations,” Archbishop Gallagher continued, quoting from Pope Leo’s address to a June meeting of the Reunion of Aid Agencies for the Oriental Churches: “After centuries of history, how can anyone believe that acts of war bring about peace and not backfire on those who commit them?”

The UN: still essential after all these years

Alistair Dutton, the secretary general of Caritas Internationalis, said in an interview with America on Sept. 23 that he was aware of the many hard realities facing the United Nations, but he retained the hope that its fortunes could be turned around. He pointed out that in the past, the United Nations has provided essential peacekeeping and mediation services in crises around the world and remains the only institution capable of focusing world attention on issues of mutual importance like climate change and human development.

He acknowledged a kind of fatigue with states whose many problems have come to appear intractable—Haiti, Sudan, South Sudan and the Democratic Republic of Congo among them. But that sense only creates a vicious cycle of indifference, underfunding and undercommitment, he argued. When the money is not invested to support its humanitarian or peace-building efforts, no one should be surprised, Mr. Dutton said, when the United Nations does not prove up to the job.

In 2015, the world’s nations agreed through the United Nations to address a gamut of interconnected global ills—hunger, poverty, the suppression of women and more—wrapped together in what became known as the Sustainable Development Goals. As states, led by the example and even the goading of the Trump administration, turn inward and sacrifice overseas relief and development funding to spend more on defense, the S.D.G.s have come to seem quaint, hopeless ambitions.

Mr. Dutton insists that they remain valuable and valid targets. “The U.S. is not wedded to them any longer,” he conceded. “And with funding falling, it’s fine to say you’ve got a goal, but if you don’t put the resources behind it, the chances of achieving it become much less. But I think as an aspirational set of goals, we mustn’t let go of them.”

“If we say it’s all dead, then you’ve got to start from scratch. We have to say, ‘No, we’ve really got some valuable instruments [in the S.D.G.s] that we can still refer to.”

His faith in the continued relevance of the United Nations is supported by the Holy See, which reiterated through Archbishop Gallagher its commitment to the work of the United Nations.

“Guided by the timeless teachings of the Catholic Church, the Holy See intends to remain a voice for the voiceless, advocating for a world where peace prevails over conflict, justice triumphs over inequality, rule of law supersedes power, and where truth illuminates the path to authentic human flourishing,” Archbishop Gallagher said.

He urged the international community to “prioritize diplomacy over division, redirecting resources from instruments of war to initiatives that promote justice, dialogue and the uplifting of the poor and of those most in need.”

The United Nations has many institutional sins to atone for. Demands for reform of the Security Council, where dinosaur seatholders China, France, Russia, the United Kingdom and the United States veto each other into perpetual stalemate on a range of global challenges, have gone unanswered. But while critics catalog its shortcomings, the United Nations currently sponsors 11 peacekeeping missions around the world, and over its eight decades, it has completed scores of other peacekeeping missions, led investigations into human rights violations, and hosted truth and reconciliation processes that have kept the peace under often fraught conditions.

The United Nations has long provided the institutional superstructure for all manner of humanitarian interventions. Its humanitarian capacity has been sidelined in Gaza by Israel with the approval of the Trump administration. But the intrusion of a politicized simulacrum of humanitarian assistance, the Gaza Humanitarian Foundation, has resulted in the deaths of thousands of desperate people, providing evidence of how badly things can go without U.N. participation.

The conflicts of the era, in Ukraine, Gaza, Sudan, and now joined by militarization and drone strikes in the Caribbean by the United States, may not have yet left the international rule of humanitarian and conflict law in “tatters,” but has surely left them “heavily strained,” Mr. Dutton said.

“We need this place,” he said, gesturing toward the U.N. headquarters across the street, “and we need to work with this place to really galvanize and get back behind a system which has helped broker peace and order globally for 80 years.”