After the world’s leaders spent thousands upon thousands of words on the subject this past week, the foreign minister of Papua New Guinea boiled it down to just six of them on Saturday.

“Unity, of course, is the answer,” Rimbink Pato said.

Maybe. Also: Maybe not. Depends on who’s talking.

The fusillade of oratory this year at the U.N. General Assembly has made clear that one of the most vexing challenges facing the planet’s nations as they muddle through the 21st century is which principle to put first: working together or going it alone.

Behind that, though, sits the larger question: What should cooperation look like in a 21st-century world?

Is it really any wonder that an organization called the United Nations — the “ultimate bastion of multilateralism,” as Singaporean Foreign Minister Vivian Balakrishnan put it — might occasionally have some tension between “United” and “Nations”?

“I admit that multilateralism is not always an easy way. But it is the only sustainable one,” Slovakian President Andrej Kiska told fellow leaders.

Part of the thorniness around multilateralism lies in the misplaced notion that it and pure unilateralism are the only choices. “Basically, there are two different views of the world,” said Marcelo Rebelo de Souza, the president of Portugal.

In reality, they sit on a continuum, and nations can stake out many points along it — particularly if they’re behemoths who can take big actions on their own or small ones who need alliances to act with any level of muscle.

Another stumbling block: Many at the United Nations this week framed U.S. President Donald Trump’s “America First” policy, outlined Tuesday, as a wholesale rejection of multilateralism.

“America is governed by Americans,” Trump said. “We reject the ideology of globalism, and we embrace the doctrine of patriotism.”

He added, pointedly: “We will never surrender America’s sovereignty to an unelected, unaccountable global bureaucracy.”

It’s true that Trump has upended chunks of the existing multilateral order. His administration has spurned collaborative entities on various levels, from renegotiating the North American Free Trade Agreement to walking away from various U.N. agencies. He has even raised questions about his commitment to NATO allies.

But compare the Trump era’s approach to that of the United States during, say, the final decade of the 19th century. He might actually come out looking like an assertive multilateralist.

Multilateralism came so far in a century of industrial and technological progress — and security needs after the second of two world wars — that even an enthusiastic isolationist today might have been a multilateralist then.

The United States has occasionally contradicted itself in this respect. Isolationist for much of its first century, it has sometimes pinballed between two founding fathers’ divergent philosophies: Thomas Jefferson, who warned of “entangling alliances,” and Benjamin Franklin, who famously said that “we must indeed all hang together, or most assuredly we shall all hang separately.”

After the League of Nations, a first attempt to unite the planet’s countries after World War I, faltered and faded, the United Nations arrived on the scene to foster cooperation in World War II’s chaotic aftermath.

It was also a time when nations aligned with the United States and the Soviet Union, respectively — in western and eastern Europe — needed to circle some wagons to stay safe. Hence the security alliances that became known as NATO and the Warsaw Pact.

Three generations later, criticisms of the U.N. as bloated, disoriented and inefficient are often paired rhetorically with dark whispers of a “one world government” that will eradicate national sovereignty. It’s an American-fueled recipe for unilateralism that other nations wary of interference in their affairs have started to echo.

“The international community must respect sovereignty of the countries,” said Peter Szijjarto, foreign minister of Hungary, which has grappled with a huge influx of refugees in recent years and is erecting obstacles to stop them.

With more vigorous unilateral actions by Washington toward the larger world since Trump took office, the chorus on the other side — hang together or hang separately — has been approaching crescendo.

That was evident this week as leaders and their posses streamed into the U.N. compound on the banks of New York City’s East River. Best guess, at least two-thirds of the countries whose leaders spoke ended up throwing in a plug for multilateralism in one way or another.

China, which has long advocated rules-based multilateralism in theory while only sometimes deploying it in practice, appeared to step in on Friday to occupy the space the U.S. was leaving behind. Foreign Minister Wang Yi reiterated China’s longtime commitment but also insisted that “multilateralism is not about making empty rhetoric. It must be pursued to solve problems.”

“There is no doubt that multilateralism needs to be defended,” Singapore’s Balakrishnan said. “That’s the only way we’re going to deal with the complex global challenges of the future.”

But how? Shouting the virtues of multilateralism from the mountaintops only echoes so far.

Look, perhaps, to British Prime Minister Theresa May for the beginnings of a nuanced path forward. As she put it, “Delivering for your citizens at home does not have to be at the expense of global cooperation.”

Figuring this stuff out, and charting a path forward, is front and center for the United Nations. These three things in particular seem to stand out:

— figuring out exactly where plain old cooperation melts into full-on multilateralism, and managing that transition smartly;

— placating those nations wary of sovereignty violations without making the U.N. an entirely toothless organization;

— establishing structures that prevent stakeholders from simply taking their toys and going home.

For the time being, at least, there are always going to be nations. United? That’s another story.

But in a world whose connections and collaborations increasingly bypass national and governmental realms entirely, it’s a conundrum the United Nations needs to solve, lest it finds itself bypassed by the very progress it tries to encourage.

“We depend on each other,” said Estonian President Kersti Kaljulaid, “whether we like it or not.”

AP