For more than two and a half centuries, the concept of unity has stood as one of the most foundational — and most contested — ideals at the heart of the American experiment. It is woven into the very name of the nation: the *United* States of America. It echoes in the nation’s founding documents, from the Declaration of Independence’s opening assertion of collective self-determination to the Constitution’s iconic opening words “We the people,” and the Pledge of Allegiance’s promise of “indivisible, with liberty and justice for all.” It is inscribed on every U.S. coin and one-dollar bill, in the Latin phrase *E Pluribus Unum* — “out of many, one.”
Yet for all its centrality to American identity, this long-held aspiration has always walked a fine line between optimism and unrealized potential, triumph and failure. It has persisted as a guiding north star through generations of struggle, and that struggle continues to unfold today, as the nation grapples anew with what unity actually means in a deeply diverse society. In an era of sharp political and social polarization, scholars are revisiting how the idea of national unity has evolved since 1776, and why the question of who belongs in “one nation” remains unresolved more than two centuries later. As Northwestern University history professor Daniel Immerwahr notes, this is a question every society across the globe must ultimately confront.
## I. The Origins of a “United” Nation: Ideals and Compromises From the Start
From the revolutionary moment that birthed the United States, the nation’s founders framed unity as the non-negotiable backbone of the new experiment in self-governance. Unlike the European monarchies the 13 colonies had broken away from, the American system would be rooted not in divine rule of a single king, but in the “consent of the governed” — a collective agreement that bound diverse former colonies into a single body politic.
As George Washington emphasized in his farewell address at the end of his second and final presidential term, the survival and success of the new nation depended on a lasting, unshakable commitment to national union. “It is of infinite moment that you should properly estimate the immense value of your national union to your collective and individual happiness; that you should cherish a cordial, habitual, and immovable attachment to it … indignantly frowning upon the first dawning of every attempt to alienate any portion of our country from the rest,” he told the young nation.
But even at the nation’s founding, when leaders stitched 13 separate, self-governing colonies into a single federal structure, a shared definition of unity was far from settled. The founders’ high-minded rhetoric of equality and collective purpose stood in stark contrast to the deep exclusions baked into the new nation: they enshrined chattel slavery, denied political and civil rights to women, Indigenous peoples, and non-white populations, and limited full citizenship to a narrow segment of society.
Today, that core ambiguity remains. Does *E Pluribus Unum* mean that diverse perspectives, identities, and experiences can blend to create a nation stronger than its individual parts? Or does it demand uniformity — that “unity” requires all people to align around a single set of beliefs, identities, and customs to belong?
Like any deep national aspiration, unity has never been achieved in a single milestone moment. Just as personal growth is built from small, consistent daily choices rather than one New Year’s resolution, a nation’s character is forged in the everyday work of living up to its stated ideals. There are no quick fixes, and no final victories.
## II. Ideals Versus Lived Reality: Centuries of Division and Struggle
Unity has stood as a core American ideal for 250 years, but the lived experience of the nation tells a different story: there has never been a single, homogeneous America, where all people shared equal access to power, opportunity, and prosperity. That gap between aspiration and reality existed at the nation’s founding, and it persists in 21st-century America.
Immerwahr notes that the United States has long had an unusually volatile history when it comes to answering the core question of unity: where to draw the line between insiders who belong and outsiders who are excluded. “What’s interesting about the United States in this regard is how changeable and nonobvious some of the answers to those questions are,” he explains.
Divisions in American life have taken many forms across generations. Some are rooted in geography, from the persistent rural-urban divide to regional differences shaped by climate and topography. Others are cultural: divides between native-born populations and new immigrants, between communities of different religious and linguistic backgrounds. Economic inequality has always separated rich and poor, shaping vastly different life experiences across class lines.
But some divides have been outright moral travesties, rooted in systemic oppression that contradicts the very ideal of unity the nation claims to uphold. For centuries, enslaved African people and their descendants were forced into chattel bondage to build wealth for white landowners; even after the abolition of slavery, legal systemic racism segregation and discrimination endured into the 20th century, and its harms echo through American society today. Indigenous nations across the continent saw their populations decimated by violence and disease as white settlers expanded westward, their lands seized, and their cultural identities systematically erased through brutal government forced assimilation policies designed to impose a narrow vision of “unity.” For generations, women, LGBTQ+ people, and other marginalized groups have been barred from full citizenship and equal opportunity on the basis of their identity.
Across every era of American history, however, excluded groups have mobilized to close the gap between the nation’s stated ideals and its lived reality. Through mass protest, legal challenge, and grassroots organizing, movements for equality have expanded access to voting, education, economic opportunity, and civil rights to more and more Americans — and they have done so by leaning into the founding ideals of unity and equality themselves.
Eileen Cheng, a history professor at Sarah Lawrence College, explains that this framework gave marginalized organizers a powerful language to challenge exclusion while still claiming their place as Americans. “It provided a language for the groups that were challenging these exclusions to draw on … invoking the ideals of the Revolution and the Declaration and saying, ‘Look, this is what the nation is supposed to be about,’” she says. “They could challenge the system and yet claim that they were the true Americans.”
## III. Reimagining Unity For a Divided Era: What Does It Actually Mean To Be United?
As an ideal, unity remains inherently abstract, and Americans have never agreed on what a truly unified nation should look like. Does unity require uniformity of belief, identity, and culture? Can a nation be united even when its people hold deeply differing views, and sit on different political sides? Is absolute uniformity even desirable in a vibrant, raucous democracy?
Around the world, different nations have arrived at wildly different answers to these questions. Some enshrine a single official language and national religion; others recognize multiple cultural and linguistic identities. The United States, for its part, has never adopted an official language at the federal level, and its citizenship model is rooted in shared commitment to a set of founding principles rather than shared ethnic or cultural lineage.
Paul Wachtel, a psychology professor at the City College of New York, argues that tension between national unity and group difference is inevitable in any diverse society. “There are always tensions between the unity and the separateness,” he says. “There’s no society that is just one or just the other … what’s really most essential is that we learn how to negotiate those tensions.”
The United States encountered this reality almost from its birth. The U.S. Constitution, the framework that still governs the nation today, was actually the second attempt at building a federal government. The first, the Articles of Confederation, prioritized state power over federal unity, and quickly proved too weak to address the young nation’s challenges — leading to the Constitutional Convention and the stronger federal system adopted in 1787.
Unlike many older nations that built their national identity around centuries of shared cultural and geographic history, the United States was purpose-built from its founding as an experiment in collective governance built on shared principles rather than shared lineage. As Immerwahr puts it: “What it is to be of the United States is to adhere to a set of principles rather than to have a certain kind of lineage. Sometimes that makes the United States remarkably open, and then sometimes that gets the leaders of the United States in all kinds of weird contradictions as they try to explain why they’re doing some forms of inclusion and not others.”
Over 250 years, the nation’s approach to balancing unity and difference has shifted constantly. Migration policy has swung between open borders that welcomed waves of new arrivals and restrictive laws that barred entire groups based on origin. Political disagreement, once seen by many founders as a threat to national unity, has become a core feature of American political life. Groups once labeled as dangerous “others” have later been welcomed into the national mainstream, and groups once accepted can be pushed to the margins in new eras of tension.
Cindy Kam, a professor of political science at Vanderbilt University, notes that the boundaries of “who belongs” are never fixed — they are actively shaped by power holders in every era. “What have we learned over the last 250 years is that things change,” she says. “We are inclined to be social animals, but what those groups are is culturally constructed. So political elites, social elites, cultural elites, they do that work in identifying what the groups are, who is part of ‘us’ and who is a part of the ‘other.’”
Today, decades of demographic, technological, and economic change have made the debate over American unity more urgent than ever. Many observers frame current rampant political polarization as an unprecedented crisis, but Cheng says that deep division is actually far more consistent with the nation’s origins than many Americans realize. “This polarization, people talk about it like it’s a new thing. But I think it’s really a return back to the way that we were at the beginning of the country,” she says. “It’s not like this kind of linear development where we’re growing more and more accepting of difference. I think it’s up and down.”
This reporting is part of an Associated Press special series marking the 250th anniversary of the United States.