- The Civil War produced thousands of wandering veterans. Frequently addicted to morphine, they were known as "tramps," searching for jobs and, in many cases, literally still tending their wounds.
- More than a decade after the end of World War I, the "Bonus Army" descended on Washington - demanding immediate payment on benefits that had been promised to them, but payable years later - and were routed by the U.S. military.
- And, most publicly and perhaps most painfully, there was Vietnam: Tens of thousands of war-weary veterans, infamously rejected or forgotten by many of their own fellow citizens.
Now it is happening again, in small but growing numbers. For now, about 1,500 veterans from Iraq and Afghanistan have been identified by the Department of Veterans Affairs. About 400 of them have taken part in VA programs designed to target homelessness.