Morton Keller

is the author of "America's Three Regimes: A Political History" and director of the Working Group on Critical Junctures in American Politics and Government at the Hoover Institution

Every so often, history comes up with an event that cries out for comparison with its analogous predecessors. Such is the latest call by President Obama for an increased military presence in Afghanistan, one of the country's series of "Small Wars." Over the last 60-plus years, we have engaged in five such conflicts: Korea, Vietnam, the Gulf, Iraq, and Afghanistan.

In each case the United States justified its involvement in terms that went well beyond the rather remote location and character of the conflict at hand. Korea and Vietnam had their ultimate source in the Cold War, and the Soviet or Chinese communist impulse to extend hegemony. In the Gulf, Iraq, and Afghanistan, it was the threat posed to our access to Middle Eastern oil, and to the region's stability, by Islamic extremism.

None of these involvements went well initially. All were bedeviled by bad strategy and tactics, or bad or misused intelligence. North Korea's initial onslaught was eventually repulsed, but then MacArthur pushed to North Korea's border with China, in the false belief that the Chinese would not intervene. They did, massively.

Lyndon Johnson chose to believe that North Vietnamese torpedo boats attacked a U.S. destroyer, and used this faulty (or imaginary) information to justify a major enlargement of the American presence in Vietnam. The result was an extended, bloody engagement which ended in a welter of domestic war-weariness and an intense, emotional public reaction.

These Cold War hot wars had hefty human as well as cultural and political costs: 58,000 American dead in Korea, 54,000 in Vietnam. Two Presidents, Truman and Johnson, were dealt mortal political blows.

Were these wars necessary? The argument can be made that the Cold War would have come to its final state - a moribund Soviet Union and a market-obsessed China - without these conflicts. But the more compelling historical fact is that the main currents of sentiment in the United States, and indeed in Western Europe, regarded these conflicts as necessary, justifiable contributions to the Cold War's end.

Will the same be said of our confrontation with Islamic militancy? To what degree do the factors that ultimately made for American success in the Cold War operate in our new, ongoing, but relatively low-key effort?

Our Iran-Afghanistan casualties so far are only a tenth or less of the Korea-Vietnam numbers. But there are disturbing dissimilarities. Post-Stalin Russia and post-Mao China proved to be far more amenable to working things out than seemed likely under those paranoid dictators. The Islamic-militant mix of the likes of Saddam Hussein and Mahmoud Ahmadinejad, and the faceless fanatics who lead al-Qaeda and the Taliban, are very different, and so far not very manageable, adversaries. Will these be succeeded by less intransigent figures? No sign of that to date.

And yet the Cold War has lessons to teach. The unpreparedness and ham-handedness that made our first Small Wars (and all of our large ones) initially so ill-managed, coexisted with qualities of adaptability that led to victory (at least on the battlefield). Matthew Ridgeway in Korea, Creighton Abrams in Vietnam, and David Petraeus in Iraq are a sequence of fix-it generals to whose ranks Stanley McChrystal may or may not be added.

Another large theme emerges from our Small Wars. Before entering the two world wars, America was convulsed by wrenching political debates over involvement. Then a massive conformity of support swept over the land: imposed in part by the government, engendered in greater part by public opinion.

Our Small Wars have followed a different course. We more or less slid into them, with little sustained debate or substantial opposition. But as the wars dragged on, widespread disapproval rose.

Yet, time and again, the protests wound up reinforcing rather than contravening the dominant policy. Eisenhower came into office in 1953 on a wave of popular distaste with Truman's handling of the Korean War. After some nuke-brandishing bluster, he extracted an armistice that easily came within the parameters of Truman's war goals. Nixon and Kissinger accepted a defeat in Vietnam that Johnson likely would have accepted. And by acceding to the agreed-on terms of U.S. withdrawal from Iraq, and quickening the pace of engagement in Afghanistan, Obama is hardly beating about the Bush doctrine.

The Small Wars have had a striking capacity to stoke domestic controversy, yet have not substantially altered the character of modern American foreign policy. World War II decisively replaced American isolationism with an ongoing interventionism, and the Small Wars since, for all their cost in blood, treasure, and internal conflict, have not (so far) changed that.

E-mail Morton Keller at keller@brandeis.edu.