If a historical turn falls into a forest of scholarship, but no one in the classroom hears it, does the turn truly occur? Maritime subject matter has experienced, of late, what Nathan Perl-Rosenthal calls a “renewal.” And if one looks only at the level of research, that observation seems indisputably true. Copious monographs, articles, and dissertations have appeared recently. Still more good work is in the pipeline. Much harder to gauge, however, has been the impact of all this inquiry at the level of undergraduate education. If the findings are not being communicated to students, are maritime scholars merely publishing into the void?

There are few dedicated maritime history courses in this country’s university catalogs. Yet I would not, for the most part, advocate for their creation. Separating out oceanic subject matter from “mainstream” narratives flies in the face of an essential truth elucidated by newer scholarship: the nearly inseparable nature of earth and water. We stand to gain new insight, multiple scholars have shown us, when we see seas and lakes as coextensive with the “landed” zones more familiar to us. Each flows into the other. Aquatic arenas facilitate interpenetration. Older generations, working under an assumption of elemental difference between sailors and their surrounding societies, isolated maritime material from larger conversations about the past. De-exceptionalizing saltwater spaces has been at the heart of recent research in the field.

That same impulse must also be borne out in the classroom. We should seek opportunities to show how maritime subjects can both broaden and deepen our appreciation of various historical phenomena. I tend to do this when teaching courses on the history of American foreign relations. In that context, sailors are essential. Prior to the Civil War, mariners easily comprised the largest cohort of U.S. citizens overseas. They dwarfed, by comparison, the diplomats and merchants more often the focus of scholarly accounts covering the early republic’s engagement with the wider world. Seafarers interacted with foreign peoples. They self-consciously introduced themselves abroad as Americans, and, in a variety of contexts, sought to project power and engage in political acts. In other words, mariners thought of themselves as the nation’s working-class ambassadors. And their observations about life overseas, meanwhile, were regularly published in newspapers, periodicals, and books. Seamen were a key conduit through which the American reading public’s ideas about the globe and its diverse inhabitants crystallized.

As such, seafarers can help introduce students to key concepts in the history of the United States in the world. Very few other communities, for example, work as well in helping to demonstrate the influence of non-state actors in shaping American foreign relations. Likewise, in tracking the perambulations of the nineteenth-century U.S. whaling fleet, we can help demonstrate globalization as an ongoing process rather than a discrete and modern event. So too do particular moments show sailors’ role in the transnational transmission of what students might otherwise misconstrue as distinctly American phenomena. One particularly pregnant episode where ordinary seamen from Commodore Matthew Perry’s expedition to “open” Japan staged a blackface minstrel show for representatives from the ruling shogunate always raises eyebrows. Finally, mariners can help students rethink conceptualizations long dominant in both our minds and our historiography. To take one such instance, manifest destiny, so important to our discussions of westward expansion, assumes new meaning and dimension when we can demonstrate its significance for sailors who deployed the phrase to justify U.S. economic penetration overseas.

That last point is an important one, and cannot be made absent maritime history: Commercial expansion and territorial expansion were not severable. They represented the proverbial two sides of the same coin. The search for export markets complemented transcontinentalism; the more land that was brought under the aegis of American enterprise, the more urgent became the need for outlets through which to channel produce, minerals, and timber. There was, in other words, an intimate connection among settler colonialism, wars with Indians, Native American dispossession, and international commodity markets. Grain shipments to Europe cannot be disentangled from the Ohio Wars and coercive treaties that cleared the Upper Midwest of native peoples. Cherokee and Creek removal was fundamentally linked to the thousands of vessels that floated cotton across the Atlantic. Beef pouring out of Chicago stockyards was a byproduct of conflicts to make the open ranges safe for cattlemen. Punishing expeditions against Apache communities in the Southwest could be measured in the flow of copper and silver throughout the Pacific basin.

These implicit linkages between terrestrial and aquatic expansion ought to be made more explicit. People at the time certainly understood the connection. As noted, America’s working-class sailors regularly spoke of their labor abroad as further confirmation of manifest destiny; eerie parallels were discerned between Indian conflict and clearance at home in the United States and events within the country’s burgeoning mercantile enclaves overseas. And over there, as much as at home, the federal government led the way. Good recent work has been done cataloguing the sustained commitment a supposedly weak and ineffectual DC establishment made, through the auspices of the Navy Department, to funding both the exploration of world oceans and launching punitive expeditions against those accused of harming American mariners. This included well-known events like the 1838–1842 U.S. Exploring Expedition into the Pacific and Commodore Matthew Perry’s “opening” of Japan, but also less renowned episodes like the Cushing mission to China, Edmund Roberts’s voyages to Vietnam and Thailand, or the destructive bombardment of the Sumatran stronghold at Quallah Battoo.

Each in its own way, these events were designed to foster an increase in exports and establish America’s dominance in the global carrying trade. Herein lay the truly international dimensions of early American expansionism: a maritime sector that circled the world, showed the flag in almost every port, built national commercial and consular outposts, exercised extraterritorial legal jurisdiction, and familiarized many foreign nations with the republic. The violence accompanying that process was spoken of, written about, and debated in terms reminiscent of expansion across the continent. The “savages” who plundered American vessels and abused the republic’s mariners would not be dealt with much differently than those who attacked western settlements. The frontier, even in the middle of the nineteenth century, was a global construct.

All of this, when packaged for undergraduate comprehension, can usefully disrupt many of the verities of the U.S. survey as they have come to understand it. Sailors are excellent teaching tools for a number of reasons. But in my experience, they are most effective in reimagining what one historian has called the “hourglass” shape of American history, which is to say, a narrative widened by the Atlantic world paradigm at one end and the War of 1898 at the other, but overly narrow or inward-looking across the intervening years. By right of the inherently international lives they led, seafarers help us to better see the embeddedness of global currents in the early life of the nation.