In the standard U.S. history course in high schools and universities, students are usually taught that until the Spanish-American War, the United States had followed for the most part the advice of Washington and Jefferson to steer clear of foreign entanglements. Americans had devoted themselves overwhelmingly to building their civilization here at home, whereas from 1898 onward, they began to “look outward” and to embrace the “large policy” of national greatness and foreign empire favored by such leading figures as Henry Cabot Lodge, John Hay, and Theodore Roosevelt. This way of dividing U.S. history into two epochs—before and after the onset of overseas imperialism—is fundamentally misleading.

Americans were empire builders from the get-go. From the moment the British colonists set foot on the North American continent, they resolved to engage in what the historians rather romantically and unreflectively call “westward movement,” which some nineteenth-century Americans characterized as the realization of their “manifest destiny.” This movement was itself an expression of imperialism, and some Americans, such as Thomas Jefferson and James Madison, were not ashamed to speak forthrightly of an American empire that would develop naturally as the (white) population grew and moved across the continent.

As my parenthetical qualification in the preceding sentence suggests, however, this vision disregarded one rather large fact: the continent across which these white people longed to expand was already inhabited by native Americans whose forebears had settled it more or less thickly over the previous millennia. The whites dealt with this difficulty by hook and by crook, doing whatever seemed expedient at the time—killing the Indians, driving them farther and farther to the west, buying their land, stealing their land, making treaties subsequently to be broken—to get the land they imagined to be theirs by divine design.

At the end of the American War of Independence, the Treaty of Paris established a western boundary for the new nation at the Mississippi River. Little by little, the Americans added huge chunks to the U.S. territory by means of an unconstitutional purchase of French claims to Louisiana (Jefferson conveniently set aside his belief in strict construction of the Constitution), an offer that Spain dared not refuse (for Florida), a settlement of disputed claims with Great Britain (to get the Oregon Country), and wars of aggression against Mexico (to snatch the southwest). By this continental imperialism, the United States pushed its western edge to the Pacific Ocean and its northern and southern boundaries deep in areas previously claimed by Mexico and Great Britain, as the map shows.

Imagine, however, that history had taken a different turn, in particular, that each of the major territories incorporated into the United States (not counting Alaska and Hawaii) had become instead an independent country. Each of them, except perhaps Florida, would have been fairly large as nation-states go. Each would have contained a vast diversity of natural resources, fertile lands for agricultural development, and long coastlines from which they could have engaged in cheap, waterborne international commerce. In short, each of these territories would have been completely viable as an independent country.

If history had taken this shape, how might the six nations of central North America have developed? Would they have gone to war with one another, perhaps shifting or blotting out their original borders, or might their leaders have seen the advantage of embracing continental free trade and friendly relations, perhaps even unobstructed flows of labor along the lines of the modern European Union? We can only conjecture answers to these questions.

One thing seems fairly sure, however: no one of these nations would have been as likely to develop into the global hegemon that the United States of America is today. And this outcome, one may well suppose, would have been a godsend for the people of other parts of the world because, however much today’s Americans enjoy whooping it up about being Number 1 and about “kicking ass” around the world with their far-flung military forces, those on the receiving end of this kicking do not appreciate it any more than the native Americans appreciated it back in the days when American imperialism was confined for the most part to North America.