Patriotism, to quote George Bernard Shaw, "is your conviction that this country is superior to all others because you were born in it." The same may be said of American exceptionalism. The phrase "American exceptionalism" has had a highly unusual career. It seems to have originated in debates in the 1920s and 1930s among American communists over whether some unique characteristic of American society inhibited the transition from capitalism to socialism. (Originally, it was employed as a term of abuse directed at those who believed - or feared - that the United States might be exempted from the iron laws of historical development outlined by Marx.) In the 1950s, exceptionalism became a weapon in the Cold War, suggesting a national responsibility to lead the forces of the Free World in the containment of Soviet power. The terrorist events of September 11, 2001, reinvigorated the rhetoric of exceptionalism as an all-purpose explanation for the attacks ("they hate us because we are free") and a new sense of American mission, now identified with the global war on terror. Most recently, American exceptionalism has emerged as a political slogan of the Tea Party and its acolytes. That President Obama "does not believe in American exceptionalism" was among the numerous charges leveled during the 2012 electoral campaign. Like his race and supposed lack of a birth certificate, this made Obama seem dangerously alien. In fact, as his administration's foreign policy became more and more warlike, Obama, like his predecessors, spoke of the uniqueness of the United States, a justification for our right to intervene in the affairs of nations throughout the world. "Long before the term itself existed, the idea of American exceptionalism was built into our culture. It has always been linked to the idea of freedom." Long before the term itself existed, the idea of American exceptionalism was built into our culture. It has always been linked to the idea of freedom. The identification of the United States as a unique embodiment of liberty in a world overrun by oppression goes back to the American Revolution. Tom Paine, in his clarion call for independence, Common Sense, called America an "asylum for mankind," a place where people fleeing Old World tyranny could find freedom. Thomas Jefferson spoke of the new nation as an "empire of liberty." This seems an oxymoron, since empire suggests domination, but Jefferson's point was that unlike the empires of Europe, ours would be based on democratic self-government. Thus, American territorial expansion by definition meant the expansion of freedom and those who stood in its way (Indians, Mexicans, rival European powers) were ipso facto freedom's enemies. Abraham Lincoln, who also embraced the idea of a unique American democratic mission called the United States the last best hope of earth - although he thought the nation should spread freedom by example, not by invading other countries (he opposed the Mexican-American War). Throughout the nineteenth century, American exceptionalism was invoked by home-grown critics, such as abolitionists, who claimed the United States was not living up to its professed values, and by the European Left, who deployed the image of an exceptional nation where workers enjoyed political rights and economic opportunity as a weapon against the status quo in their own countries. Others (most famously Werner Sombart) cited the high American standard of living to explain the relative weakness of socialism compared to early twentieth-century Europe. To a considerable degree, the essence of American exceptionalism - a nation state with a special mission to bring freedom to all mankind - depends on the "otherness" of the outside world, so often expressed in the manichean categories of New World versus Old or free world vs slave. Yet, at the heart of the idea lies an odd contradiction. American freedom is generally held to derive from a specific national history and unique historical circumstances - the frontier, the qualities of the Anglo-Saxon race, a divinely appointed mission, and so forth - and yet Americans claim for their experience and ideals universal relevance. America may be exceptional, but its exceptional role is to serve as a model for the rest of mankind. Presumably, when our self-appointed mission of promoting the worldwide spread of freedom has finally been achieved -- when the world has become America writ large -- America will no longer be exceptional. "At its best, the idea of American exceptionalism carries with it healthy pride in the freedoms Americans enjoy. But overall, the insistent claim for exceptionalism goes along with national hubris and closed-mindedness, and offers an excuse for ignorance about the rest of the world." At its best, the idea of American exceptionalism carries with it healthy pride in the freedoms Americans enjoy. But overall, the insistent claim for exceptionalism goes along with national hubris and closed-mindedness, and offers an excuse for ignorance about the rest of the world. Since the United States is so exceptional, there is no point in learning about other societies, as their histories have no bearing on ours. Historians, unfortunately, have aided and abetted this parochialism. Perhaps the most original idea ever developed by an American historian was Frederick Jackson Turner's frontier thesis, which explained the country's supposedly unique characteristics - political democracy, self-reliant individualism - as the product of the struggle to subdue the West. Cold War intellectuals provided historical justification, differentiating "good" from "bad" revolutions. In the 1950s, historians portrayed the American Revolution as a decorous constitutional debate among the educated elite, quite different from the class-based violence of revolutionary France and Russia, or Third World revolutions led by communists (even when, as in Vietnam, they invoked the American Declaration of Independence). As the historian Herbert Bolton complained many years ago, by treating the American past in isolation from the rest of the world, historians were helping to raise up "a nation of chauvinists." Of course, the history of every country is, to some extent, unique, and the antidote to American exceptionalism is not to homogenize the entire past into a single global history. But the institutions, processes, and values that have shaped American history, among them the rise of capitalism, the spread of political democracy, the rise and fall of slavery, and international labor migrations, can only be understood in a global context. To be sure, as Robin Blackburn reminds us in his recent hemispheric history of slavery, international processes are worked out within specific national histories. The exceptionalist paradigm, however, homogenizes the rest of the world as having a single history, entirely different from that of the United States. Much writing on exceptionalism is based on sheer ignorance of other countries - the United States, we are told again and again (falsely) has the highest standard of living in the world, the highest rate of social mobility, the greatest racial and ethnic diversity, the most individual freedom, the least political radicalism, etc. Oddly, one genuine expression of American exceptionalism - the principle, embedded in the Fourteenth Amendment, that anyone born in the United States is automatically a citizen, regardless of the status of the parents - is now under assault by the very conservatives who so stridently proclaim their devotion to the exceptionalist paradigm. "...the history of every country is, to some extent, unique, and the antidote to American exceptionalism is not to homogenize the entire past into a single global history... The exceptionalist paradigm homogenizes the rest of the world as having a single history, entirely different from that of the United States." The historical and political uses and abuses of exceptionalism came together in 2009-10 in the debate over health care reform. A century ago, as Daniel Rodgers reminds us in his book Atlantic Crossings, American reformers and social scientists eagerly studied European responses to the crises of urbanization and industrialization. They thought European experiences could contribute to the development of American social policy. Fast forward to 2009-10. Every advanced country in the world has some kind of national health care system. But in American debates, no one thought to refer to their experiences, except to hurl abuse. Obamacare would bring about the alleged horrors of the British National Health Service, or Canadian single payer health insurance - abuses "known" through rumor and invective, not actual investigation. All sides made a virtue of isolation and ignorance. Here is the deepest problem of American exceptionalism - the conviction that Americans have nothing to learn from the rest of the world.