If he were alive today, William McKinley would understand Barack Obama's 2011 humanitarian intervention in Libya. Like Obama, McKinley confronted geopolitical disorder and economic distress wrought by swashbuckling capitalism. As Commanders-in-Chief and liberal Protestants, the twenty-fifth and forty-fourth presidents both confronted the knotty issue of humanitarian intervention.

Until recently, historians conceived of humanitarian interventionism as a policy with shallow roots in America. Seemingly born from what J. Daryl Charles calls the "defects of the post-Cold War period," American forays into Somalia, Bosnia, and Kosovo have been described as ad hoc and lacking precedent. Such observations reflect a misunderstanding of America's deep history with humanitarian intervention.

At the center of this misunderstanding is religion. The U.S. is the only major industrial democracy where religion still permeates contemporary society as it did three centuries ago. Many analysts have failed to recognize the extent to which religious thinking infuses U.S. foreign policy.

Obama and the Libyan Intervention

Obama's first humanitarian intervention was multilateral and restrained, designed merely to stop an imminent massacre and offer Libyans an opportunity to overthrow dictator Muammar Qaddafi themselves.

Libya's uprising began in February 2011. It was a byproduct of the Arab Spring, prompted by similar issues of government corruption and economic malaise.

Erratic and borderline delusional, Qaddafi was no garden-variety autocrat. Armed with a messianic vision and his revolutionary Green Book, Libya's "Brother Leader" seemed more Mao Zedong than Hosni Mubarak.

But despite his declared benevolence, when provided an opportunity Libyans revolted en masse. Within weeks of the popular uprising's genesis, rebels controlled much of the nation. By early March, they even threatened the capital, Tripoli.

Flush with oil money, Qaddafi employed sophisticated armaments to crush and roll back the lightly armed and untrained opposition. Supplemented by foreign mercenaries, by mid-March government forces slowly pushed toward the rebels' stronghold, Benghazi. Wantonly slaughtering civilians, Qaddafi's forces appeared poised to take the city, destroy the rebellion, and butcher the inhabitants.

As March crept toward April, Qaddafi presented Obama with a stark choice: stage a humanitarian intervention or witness horrendous carnage. Stuck between the realists, who preached against intervention, and the neoconservatives, who urged an immediate NATO air campaign, Obama opted for a multilateral approach. (He was later ridiculed for "leading from behind.")

Transforming a French "no-fly zone" resolution into a UN-sanctioned military intervention, the administration achieved a diplomatic triple play. Endorsed by the Arab League and publicly pushed by the French, the UN approved its first-ever military action to stop an "imminent massacre."

Though messy, NATO airstrikes and military aid did turn the tide and enable the rebels to depose Qaddafi.

The primary influence on Obama's nuanced humanitarian intervention—as with McKinley's intervention in Cuba in the 1898 Spanish-American War—was the long-standing idea of the American sacred-secular world mission, combined in Obama's case with the influence of twentieth-century philosopher Reinhold Niebuhr.

The Sacred-Secular Mission

The Puritans' Reformed Protestantism remains the alpha and omega of U.S. foreign policy and still shapes Americans' view of their role in the world.

Key to understanding the connection between the seventeenth and twenty-first centuries is the Puritans' "destinarian" zeal. As a radical schism of a messianic outlier in Europe's Protestant movement, the Separatists saw their march into the wilderness as nothing less than a journey to save the world. Four centuries later, U.S. foreign policy still bears the destinarian imprint.

Anders Stephanson has argued that the founders of the U.S., taking the baton from the Puritans, conceived their new nation as a "sacred-secular project, a mission of world-historical significance in a designated continental setting of no determinate limits."

Thomas Jefferson's political thought and presidential action reveal the sacred-secular mission fueling nineteenth-century U.S. foreign policy. The third president's "empire of liberty" amounted to more than acquiring the Louisiana territory for settlement. In his mind, it constituted a move toward the universal liberation of humanity.

While the Puritans' distinctive Calvinism ebbed, their proselytizing ardor remained influential among American leaders. A hopeful offshoot of a religion founded upon expectation, nineteenth-century Protestantism maintained the founders' emphasis upon millennial progress. Fusing republican ideology into their theology, American Protestants boasted, Mark Noll has written, a "nearly messianic belief in the benefits of liberty … and the providential destiny of the United States."

Nineteenth-Century Humanitarianism

While naked self-interest and chauvinism propelled westward expansion, "Manifest Destiny" also justified Americans' sacred-secular project. With faith in Jesus, liberal individualism, and belief in America's millennial destiny, Protestants pushed west.

Once the frontier closed, however, Americans sought new outlets for their destinarian impulses. Moved by genuine charitable impulses and as an emergent power, they found one in the burgeoning humanitarian movement.

"Humanitarianism" and humanitarian intervention—governments acting to protect human life beyond their borders—do not usually play significant roles in most historical treatments of nineteenth-century diplomacy. Indeed, the nineteenth century has a well-deserved reputation as the heyday of European and American imperialism and realpolitik.

In spite of this reality, humanitarian sensibilities did influence Western foreign policies. Whether it was anti-slavery agitation on both sides of the Atlantic or the 1885 Berlin Treaty, a distinctly modern version of "humanitarianism" increasingly informed Western, democratic foreign policies.

Initially catalyzed by the "teeming mass of ideas" linked to the American and French Revolutions, the humanitarian "association mania," as the London Times dubbed it, flourished in America. Humanitarianism was a decidedly liberal project premised on the Enlightenment's fundamental hypothesis that all human life is equal.

The American and French Revolutions' emphasis on natural rights along with the emergence of the mass press, public opinion, and participatory government helped transform humanitarianism into a mass movement. More importantly, these ideological and institutional developments made humanitarian intervention both politically possible and popular.

Humanitarian sentiments were not limited to the foreign policy sphere. Early nineteenth-century British and American nationalists fancied their countries world liberators in the age of revolution.

Britons regularly bandied their slave trade ban as proof that they remained at the vanguard of human rights. Picking up this cue, early American abolitionists pushed for the eradication of slavery from a distinctly modern, humanitarian worldview. In part, abolitionists sought to eradicate slavery to maintain America's status as global redeemer.

The "CNN Effect"

The "CNN effect" is a theory that modern news coverage, exemplified by the 24-hour international news network, began during the Cold War to significantly shape foreign policy by generating public outcry at images of human suffering. However, the media's ability to depict individual anguish, shape public opinion, and create calls for intervention certainly existed prior to cable news.

Indeed, rising literacy rates across Western Europe and America caused the proliferation of newspapers and magazines, which performed the same functions as television does today.

In large part, humanitarians pushed for global action due to the influx of news, which enabled them to read about and view images of human suffering as never before. During the 1890s, the international telegraph, along with the maturation of Reuters and Associated Press news services, allowed newspapers and magazines to more easily report international news. For example, the Christian Herald and Harper's regularly publicized Turkish atrocities committed against Armenians.

New photographic technologies rendered human suffering all the more real to readers. In the Harper's 1895-96 series "The Troubles in Armenia," editors used eleven-by-sixteen photolithographs and drawings graphically depicting the Armenians' "utter extinction." American opinion leaders such as Julia Ward Howe and Charlotte Gilman Perkins called for intervention.

In conjunction with newspapers and magazines were books, like Frederick Greene's bestseller, The Armenian Crisis in Turkey, which further publicized the slaughter. Greene also pleaded for U.S. involvement.

The Iowa Russian Famine Relief Commission

Humanitarian intervention in the nineteenth century was not a top-down endeavor led by the White House. Instead, it was a grassroots movement emanating from the nation's educated middle class. America's first humanitarian intervention emerged as a private venture.

In response to the 1892-93 Russian famine an obscure Davenport, Iowa newspaper editor, Benjamin Franklin Tillinghast, launched a national famine relief effort. Much more than simple charity, the Iowa Russian Famine Relief Commission created a new chapter in U.S. diplomatic history.

Quintessentially American, the effort emanated from sacred-secular tendencies but was coordinated from Tillinghast's newspaper office. Lacking federal oversight, military transports, or bullets, what became a national famine relief enterprise nevertheless constitutes a humanitarian intervention. In foisting 32,000 tons of food and hundreds of foreign observers, media and relief workers upon a reluctant Tsar, Americans effectively barged into the internal affairs of a sovereign state.

Trumpeted by President Benjamin Harrison, governors, and celebrities, the effort grew in popularity. Ultimately, the endeavor also helped condition voters and politicians to accept humanitarian interventions as a legitimate foreign policy expression of the traditional American mission.

Within three years of the creation of the Iowa Russian Famine Relief Commission, Congress debated the merits of militarily intervening to stop Ottoman atrocities against its Armenian subjects. Despite significant activism, President Grover Cleveland refused to act. Once again, private citizens stepped into the breach.

Flanked by relief organizations and Tillinghast's committee, Clara Barton negotiated access to the Armenians and directed the American Red Cross's first humanitarian intervention onto foreign soil. The excursion established yet another precedent for intervention.

It also ensured Armenia remained a potent political issue. In response to Cleveland's continued dithering, the 1896 Republican platform explicitly called for action to "bring these atrocities to an end."

In justifying the Spanish-American War two years later, McKinley referred to the "many historical precedents where neighboring States have interfered … to check the hopeless sacrifices of life by internecine conflicts beyond their borders." The president merely followed where the American people had already led.

Despite Barton's humanitarian aid, an estimated 186,655 Armenians died in the autumn of 1896 alone. The memory of the failed cause loomed large when Americans turned their attention to Cuba. In the days leading to McKinley's declaration of war, the New York Times equated Armenia with Cuba.

"The barbarities of the Spaniard, like the barbarities of the Turk, are … essential to his rule … [a]s Europe recognizes that to put a stop to Turkish misrule it is necessary to put a stop Turkish rule … so we must recognize that to pacify Cuba Spain must go."

Realizing this, Cuban rebel leaders used the specter of "Armenia" as a propaganda tool to maintain the American public's interest in the conflict.

The Spanish-American War as Humanitarian Intervention

As the proverbial ugly stepchild of American diplomatic history, the Spanish-American War occupies complicated territory. Because foreign policy specialists realize the war's imperialist results, many are reluctant to identify it as a humanitarian intervention.

Humanitarian concerns, however, paved McKinley's path to war. Even though the conflict had imperial consequences, the president's rationale should be considered separately from the war's outcome.