I do not know the totality of the situation involving the two bombers, What I do know is that strategically it does not make a lot of sense for the Taliban or Taliban linked elements to have carried out or to have sponsored this attack. For all intents and purposes, things are going the Taliban’s way in Afghanistan, We have established a timeline in which we will be departing and any attack on American soil would have the opposite effect of ensuring that departure. The Taliban is a political entity that uses terrorism and criminal activity to further their political agendas, Al Queda on the other hand is a Terror organization who’s purpose is to commit acts of Terrorism to right perceived wrongs. There is a fundamental difference in methodologies and tactics. The Taliban for example wishes to resume power or have a power sharing role once the US and NATO departs and are currently negotiating toward achieving that end. Al Queda simply wishes to commit as much carnage as possible to highlight their grievences and hasten the departure of western influence in the Muslim world. In other words, The Taliban and any Terror organization would more than likely be on opposite ends of this attack. That does not mean of course that the Taliban would neccesarily grieve at the loss of American lives, it means that the attack does not serve their interests. Only time will tell the motivations of the two who carried out the attack and whether or not they were a part of a much larger organization and whether or not they were sponsored by a terror organization, a nation state or became radicalized on their own.