NYT:
What does this mean for Iraq? At the least, Tet and Somalia suggest we should be very careful before concluding that Iraq is a defeat. There is real evidence of failure, especially the escalating sectarian violence. But our perceptions are nevertheless easily manipulated. Iraq looks like a defeat in part because the Bush administration fell into the same trap as President Johnson: raising expectations of imminent victory by declaring “mission accomplished” before the real work had even begun. And as with Somalia, fighting shadowy insurgents in Iraq while propping up a weak government engenders negative memories of Vietnam.
Perceptions of success and failure can change the course of history. Reeling from the supposed disaster at Tet, the United States began to withdraw. Memories of “failure” in Somalia were a major reason — perhaps the major reason — that the United States did nothing to stop the genocide in Rwanda in 1994. If Iraq is perceived as a failure, it is only a matter of time before America pulls out, leaving who-knows-what behind. With the stakes so high, Americans must be certain that their perception of failure in Iraq is not a mirage.
Here.