It's apparent now that Osama bin Laden's assassination of the military commander of the Afghan opposition was a prelude to the attacks in the U.S. This was a critical part of his plan to delay our reaction.
Masood was the single man capable of uniting the Afghan opposition against the Taliban. There is noone left who can truly replace him. He will be missed.
Still, the Northern Alliance can play a vital role in our retaliation against Osama bin Laden and the Taliban in several ways -
They can provide intelligence, logistical support and a forward base of operation from their territory. This is important because we can't necessarily rely on Pakistan, Tajikistan or Russia to do that.
And when our operation is completed, they can provide a pro-Western government to replace the Taliban in Afghanistan.
Problem is do we need those kinds of allies? Iran? Pakistan? We may be setting ourselves up for another "blowback" with our new allies. Maybe we are better off with just Russian (and her commonwealth states) and Indian help. FOrce Pakistan to help without using her as a base (it is an unsafe country), allow the the Chinese and Iran to help but at a distance.
Maybe something good can come out of it.