Iraq is not Vietnam. Really. But when President George W. Bush, the king of denial, can bring himself to liken the recent upsurge of violence in Baghdad to the 1968 Tet offensive, we know the similarities are too big to ignore. Worse yet, although Vietnam and Iraq are more different than the same, few of the differences point to a better outcome.

The main similarity between the two tragic wars is that the most powerful country in the world proves unable to impose control on a far weaker one in spite of years of military, political and economic effort. In both cases, an American public willing to sacrifice blood and treasure for success loses patience when promises of progress are belied by inconclusive combat and worsening disorder.