A corrupt government that has alienated many of its people finds itself unable to overcome a growing insurgency in an endless civil war and expects a superpower on the other side of the globe to come to its rescue. That's the story in Iraq today -- which carries eerie echoes of the not-so-distant past.
In June of 1964, as conditions deteriorated in South Vietnam, President Lyndon Johnson assured a journalist he was not about to get too far in or stay too far out. "We won't abandon Saigon, and we don't intend to send in U.S. troops," he insisted. He was betting that U.S. military advisers would be enough to head off defeat.
Half a century later, President Barack Obama has adopted a similar policy, dispatching some 300 advisers to Iraq in an effort to keep its military from being routed. Once again, the fervent hope in the White House is that a small commitment will suffice.
The difference is that Obama's decision comes in the aftermath of a catastrophic American intervention, following our departure, rather than at the beginning of one, as we're about to plunge in. It's an epilogue, not a foreword.
But the parallels between the two wars are more conspicuous than ever. And there are clear morals to be drawn from them. Some of the big ones:
--Military power is overrated. The United States had huge advantages in technology, resources and manpower over the North Vietnamese and their Vietcong confederates. Our soldiers prevailed again and again in combat. But victory eluded us.
Same in Iraq. We smashed Saddam Hussein's army with devastating speed. But we were unprepared for the subsequent guerrilla war, fought with improvised explosive devices and suicide bombs. The insurgents had no chance of defeating American units in conventional battles. But they didn't need to.
--Motivation is critical, and we can't supply it to our allies. The U.S. spent some eight years and $25 billion training the Iraqi military, which greatly outnumbered the fighters of the Islamic State in Iraq and Syria (ISIS). But when ISIS launched an offensive this month, the government forces dissolved like sugar cubes.
The militants have succeeded despite many disadvantages. They have one big advantage, as an Iraqi commander told The New York Times: "ISIS fighters have a will to die, so they don't show fear."
The same was true of the enemy in Vietnam. Our South Vietnamese allies were notoriously unreliable, while Communist soldiers fought doggedly despite horrendous conditions. "'I wish they were on our side' was a comment commonly uttered by American officers," wrote Stanley Karnow in "Vietnam: A History."