It is too soon to tell what is going on in Kabul right now, but folks are raising the Tet parallel all over the place, including on unrelated blog posts of mine.
My first take: the Taliban aspire to Tet but are too late. That is, Tet was a key turning point because it changed expectations about what was happening in Vietnam, forcing a series of political decisions and changes, including LBJ not running for re-election and the end of escalation. In Afghanistan, the Taliban may be attempting to score a similar blow, but it will not affect US domestic politics in the same. Why? Because the US and its NATO partners have already begun the process of getting out. In 1968, there was no end in sight, with the US commitment seemingly forever enduring. In 2011, the clock has been ticking for a while, with 2014 very much on the horizon.
My second take: the Tet parallel is apt in one way. All that stuff we have been hearing about decapitation of the Taliban must be, ahem, exaggerated if the insurgents can coordinate this well. To be clear, I am not saying that the US/NATO forces have been lying about how many middle-level managers have been getting captured or killed, just that the effects may have been overplayed.
My third take: war is bargaining by other means. Lots of stuff lately about the Taliban meeting with the US and such. The surge was aimed not so much at victory perhaps but stopping the insurgency's momentum--so that bargaining could proceed. This attack might be a way to re-shift the bargaining space as it shows that the Taliban's powers are not all gone.
So, this might be Tet-esque but no more than that. Still not good news for anyone, but we need to be careful about which parts of the analogy seem to apply.