Or so argues Marvin Weinbaum:
For some time now, the Taliban, by their words and deeds, have shown that they lack interest in compromising with the Karzai government or its international allies. The idea that Mullah Omar’s Quetta Shura or the Haqqani leadership would bid for cabinet positions or provincial appointments was an essentially Western notion. It assumed that the Taliban could be induced to accept a democratically inclined, coalition government that could also constitutionally incorporate their Islamic doctrinal aims—this with a movement whose leadership has never shown much tolerance for those who did not share their particular worldview.
Earlier commentary along these lines here.