Andrew Carnegie, center, in front of a railroad tunnel under construction in 1885 in Pennsylvania. (Associated Press)

David Oshinsky, director of the Division of Medical Humanities at the NYU Langone Medical Center, is the author of “Bellevue: Three Centuries of Medicine and Mayhem at America’s Most Storied Hospital.”

In February 1941, as the armed forces of Nazi Germany, facist Italy and imperial Japan gobbled up great chunks of the globe, Time-Life publisher Henry Luce penned an editorial that resonates to this day. Calling upon Americans to accept their unique responsibilities and God-given destiny, he wrote: “Throughout the 17th Century and the 18th Century and the 19th Century, this continent teemed with manifold projects and magnificent purposes. Above them all and weaving them all together into the most exciting flag of all the world and of all history was the triumphal purpose of freedom. It is in this spirit that all of us are called, each to his own measure of capacity, and each in the widest horizon of his vision, to create the first great American Century.”

Pulitzer Prize-winning historian Steven Hahn would respectfully disagree. Freedom has long been among the most elusive of our national goals, far from triumphant, he argues in “A Nation Without Borders,” a massive and masterly account of America’s political and economic transformation between 1830 and 1910. As to the first great American century, Hahn is certainly partial to the 19th — the one, he says, in which the United States harnessed its unrivaled resources to forge a new kind of empire. What happened afterward was simply an extension of what came before.

Hahn, a recent addition to the history department at New York University, where I hold a part-time appointment, views the American experience as a continuum of an imperialist ideology dating back to our British forefathers. Expansion of one sort or another, he insists, is part of our national DNA. Whether clearing Native Americans from their land, obtaining close to 800,000 square miles from France in the Louisiana Purchase, or defeating Mexico in a one-sided fight that added Texas, California and much of the Southwest to the American map, the pursuit of empire — or Manifest Destiny — became a unifying force, supported by merchants looking for new markets, slaveholders dreaming of new possibilities in far-flung places like the Caribbean and small farmers seeking no more than a plot of land to till.

The problem, Hahn says, is that the young United States lacked the capacity to govern and develop the land it acquired. The watershed moment, in his view, was the Civil War. Without slighting the momentous changes (and missed chances) generated by the conflict in terms of slavery, freedom and Reconstruction, Hahn opens a wider lens. Before the war, the United States was an agrarian nation with a weak central government and political power dispersed among the states and localities. Its ruling elites had come from the merchant and slaveholding classes. There was no national currency, no central bank, no transcontinental railroad, no firm connection between the political and economic sectors that we take for granted today.

"A Nation Without Borders: The United States and Its World in an Age of Civil Wars, 1830-1910," by Steven Hahn (Viking)

The war changed all that. To recruit and supply an enormous army, President Abraham Lincoln, along with Congress and the federal courts, assumed unprecedented authority, including the power to suppress dissent. Huge government contracts were awarded to foundries, shipyards and factories. In 1861, Hahn writes, Congress “enacted a modest tax on incomes over $800 and . . . passed the Legal Tender Act, which authorized the circulation of . . . noninterest-bearing Treasury notes, known as greenbacks.” Hoping to move troops quickly and to populate the western territories with small farmers rather than slaveholders, the government promised 160-acre homesteads to families willing to work them, and encouraged railroad-building projects of staggering size and often dubious value. By war’s end, Hahn says, “a new class of finance capitalists” had arisen for these purposes, known popularly over time as Wall Street.

Hahn paints the latter half of the 19th century as an era of unchecked corporate expansion and imperial conquest. It hardly mattered which political party held office in Washington — though it was mainly the GOP — because the results barely differed. Following a brief moment of hope, newly freed Southern slaves found themselves abandoned to their former oppressors in the name of sectional reconciliation and economic stability. In the trans-Mississippi West, which Hahn views as the key region of this era, Native Americans were pushed aside to make way for the settlers, railroads, gold miners and extractive industries that fueled the industrial revolution. Hahn rightfully spends a lot of time on Indian removal, viewing it as a critical element in the drive for an empire stretching physically to the West Coast and commercially to the great Pacific trade routes beyond.

In Washington, meanwhile, massive lobbying efforts backed by naked corruption led Congress to turn over more than 100 million acres of public land to private railroad, coal and iron interests. A new class of cattle barons emerged, powered by open-range grazing policies that allowed them to feed their herds on the way to slaughterhouses hundreds of miles away. The “money question” — whether the nation should embrace a national currency backed by hard specie like gold, the favorite of powerful lenders and creditors, or a more inflationary system favored by chronic borrowers and debtors — ended in defeat for the latter. As labor unions formed, with demands for higher pay and better working conditions, the new corporate elite, led by the likes of Andrew Carnegie and John D. Rockefeller, had little trouble persuading the courts and even the White House to call in federal troops to arrest strike leaders — and protect strikebreakers — in the name of safeguarding private property and restoring law and order. And when Congress occasionally roused itself to pass a bill designed to break up monopolies, corporate lawyers could count on the fiercely pro-business Supreme Court to gut the legislation.

As the 19th century gave way to the 20th, all was in place. “The national banking system would be preserved, the railroads and telegraphs would remain in private hands, and talk of greenbacks and free silver would be banished to the margins.”

America had become a nation without borders, Hahn asserts. Taking a page from William Appleman Williams and previous revisionist historians, Hahn speaks of an American imperialism based on economic rather than physical domination. Unlike England, for example, the United States didn’t have to plant its flag — its troops and administrators — in far-flung regions of the world. All it needed, given its growing commercial dominance, was a level playing field, or “open door,” backed by a navy to keep the sea lanes open and an occasional acquisition (Hawaii, the Philippines) or intervention (Cuba, Mexico) to ensure its superiority.

In portraying this era as a struggle between the haves and have-nots, Hahn leaves some key questions unanswered. While providing superb capsule summaries of individual reformers and collective protests against the new capitalist order, he doesn’t confront the issue of why so many of these movements failed to catch fire. Was it because of repression by the powerful or the fact that many Americans had little sympathy for the grievances and panaceas bubbling up. Is it possible — indeed, likely — that more people benefitted from the nation’s colossal riches, however unevenly distributed, than some would care to admit? The answer, almost certainly, is yes.

Hahn describes his book as telling “a familiar story in an unfamiliar way.” It is much more than that. Attempting a synthesis of a century’s worth of American history is a daunting task. Writing one as provocative and learned, if at times predictable, as this one is a triumph, nothing less.

A Nation Without Borders
The United States and Its World in an Age of Civil Wars, 1830-1910

By Steven Hahn

Viking. 596 pp. $35