The word "Vietnam" is being muttered more and more in Washington. But is there any sense in the comparison?
It's important to note why people are referring to that traumatic war. It is not that anyone thinks the conflict in Afghanistan will cause the bitter fissures in American society that Vietnam broke open. Iraq didn't come close, and Afghanistan certainly won't.
What they are talking about is the idea of pinning hopes of victory on increasing troop numbers, winning hearts and minds and building up a government that many think doesn't deserve to be supported.
I wrote about a conversation with ABC's chief pollster, Gary Langer, yesterday, but after our interview he showed me some fascinating data. On two almost identical graphs, two intertwining lines plummet downwards. One line is presidential popularity and the other the popularity of a war. The first is LBJ and Vietnam, the second Bush and Iraq.
"That's what Obama will be worried about," says Gary, adding that if a bad economy destroys presidencies, an unpopular war does the job even more effectively. "Vietnam" is simply shorthand for "quagmire".