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.