As President Biden’s first international trip recedes into the rearview mirror, it is an opportune time to take stock of the overarching theme of his tour, namely that “diplomacy is back.”

Biden will tout the agreement among the G-7 nations on a corporate global minimum tax, and his summit withRussian President Vladimir Putin has generated the most discussion, but Biden and British Prime Minister Boris Johnson’s negotiation of a “revitalized Atlantic Charter” epitomized Biden’s emphasis on diplomacy.

The new Atlantic Charter references the myriad challenges now facing the world, and commits to “institutions, laws, and norms” to strengthen democracy. It is much like the original 1941 version, which was an idealistic statement of war and peace aims negotiated by President Franklin D. Roosevelt and British Prime Minister Winston Churchill. The original committed the U.S. to the cause of building a new world order after the “final destruction of the Nazi tyranny.”

Both the original and revived Charters articulated new “grand strategies” — laying out goals for international relations and the means for achieving them.

But the main lesson of the original Atlantic Charter is that whether the new document achieves its promise will depend on what the public and policymakers do next and whether its ideas permeate the public consciousness and become a new guidepost for international relations.

By August 1941, Nazi forces had taken most of Europe and were on the march deep into Russia. The U.K.’s situation looked increasingly bleak. Roosevelt and Churchill met clandestinely off the coast of Newfoundland.

Their conference produced a trim, eight-point, 800-word “Joint Declaration.” It spelled out British and — rather astonishingly considering the U.S. was not yet at war — American war aims for the post-war world.

Initially published as a telegrammed news release, the Atlantic Charter was neither a treaty nor a formal agreement.

Yet upon closer scrutiny, the Charter’s bold, world-shaping ambitions stood out. In signing on, Roosevelt took a major political risk. He riled up the vociferous, anti-interventionist opposition back home — notably the America First Committee. And, without Congress formally on board, he probably committed the U.S. to joining the war, presenting possible constitutional issues.

The ideas the original Charter embodied were as audacious as the overall commitments. They centered on three themes.

First, the Charter incorporated idealistic World War I-era Wilsonian propositions, including respect for national sovereignty and self-determination.

Second, it included new security mechanisms among allies to promote goals such as free trade and disarmament. The two leaders kept these provisions deliberately vague so as not to invoke the specter of the failed League of Nations.

Third, most importantly, the Charter accentuated a group of points promoting what one Roosevelt aide called “the development of the human personality.” This classic New Deal phrase suggested policies such as improved labor standards, economic advancement and social security.

The Charter’s lone lyrical passage called for the establishment of “a peace which will afford to all nations the means of dwelling in safety within their own boundaries, and which will afford assurance that all the men in all the lands may live out their lives in freedom from fear and want.” Churchill inserted this last phrase to flatter Roosevelt. It was a deliberate echo of the president’s 1941 State of the Union address — which had called for the “Four Freedoms” — freedom of speech and worship, and freedom from fear and want.

Different constituencies interpreted the agreement in widely varying ways.

Churchill himself was clear that he intended the Atlantic Charter as a polemic to buck up British spirits, as well as those of various European nations suffering under Nazi occupation. Roosevelt’s domestic critics suggested that Churchill had basically duped the president into signing on to an imperial morale-builder. But this take only narrowly interpreted the Charter’s vague and expansive language.

By contrast, Roosevelt and his aides saw the document as laying out a New Deal-like vision for the world. It linked a world order in which “justice rather than violence” guided decisions with promoting “the fullest development of the national resources of all nations and the fullest participation of all peoples in the gains of civilization,” in the analysis of one Roosevelt adviser. Just as the New Deal fundamentally reconfigured the idea of security for the individual citizen, the Atlantic Charter reframed international security to include explicit social justice dimensions.

The most radical take on the Atlantic Charter came from those fighting colonialism and racism like future South African president Nelson Mandela. Mandela wrote in his memoirs that the Charter “reaffirmed faith in the dignity of each human being and propagated a host of democratic principles.” Those in Africa, Mandela continued, “hoped that the government and ordinary South Africans would see that the principles they were fighting for in Europe were the same ones we were advocating at home.” This interpretation envisioned the Charter as an anti-colonial instrument that implicitly recognized the standing of the individual everywhere in the world.

These interpretations wildly conflicted with one another. And it was only what came after Roosevelt and Churchill released the document that determined which perspective would prevail.

As the war took a turn for the worse in 1942, it pushed new ideas into the public sphere. The Atlantic Charter gained traction in part thanks to an unexpected cultural intervention in the U.S.: The Saturday Evening Post began publishing Norman Rockwell’s “four freedoms” paintings. These images of home and hearth would go on to serve as war bond advertisements and become among the most recognizable images published during the war.

This kind of aspirational propaganda helped define the war’s aims in the public mind, popularizing the ideals embedded in the Four Freedoms and the Atlantic Charter. The images — and related public rhetoric, including propaganda efforts — simultaneously challenged and inspired millions of Americans to be the opposite of the totalitarian opposition. Where Nazis were racists, Americans should become more tolerant (albeit without displacing the brutal Southern Jim Crow regime). Where Nazis suppressed free speech, Americans should support speaking out.

These binaries gave purpose to the war effort and helped bring the Rooseveltian interpretation of the Atlantic Charter to life.

Which version of the new Atlantic Charter will prevail moving forward?

Just like the original, the new Atlantic Charter understands that American involvement in the world needs to be firmly rooted in domestic policy and democratic commitments. It is premised, in fact, on the explicit recognition that democracy needs to be sustained by domestic practices, throughout the world.

Like the original, the new Charter also reimagines security and stability; this time it includes debt relief and “high labor and environmental standards” in addition to more traditional aspirations such as arms control.

One difference between the two Atlantic Charters is that the new one mentions human rights and dignity explicitly, envisioning them as a starting point for the world order, whereas the original only became a human rights instrument over time.

In revitalizing the old Charter, Biden — who is self-consciously modeling his presidency on Roosevelt’s — and Johnson, whose father has favorably compared his governing to Churchill’s, implicitly make the case that 2021 is like 1941, with the world again at a momentous inflection point.

And their case here is strong. As in 1941, threats to democracy in the U.S. and around the world are real and proliferating. The human and economic costs of covid-19 have been devastating and are far from over, especially outside of the U.S. The climate crisis is worsening. The world is at a crossroads.

Biden clearly hopes this Charter will help to propel his own New Deal domestically, as well as serving as one of the building blocks for restoring America’s role in the world after the presidency of Donald Trump.

Whether the new Charter turns out to be a liberal, conservative or radical document will depend on what happens next. As in 1941, the power of the ideas and the vision, not the agreement itself, are likely to matter most. As Churchill explained in 1942,” The Atlantic Charter is not a law,” where enforceability matters most, “it is a star.”