The fugitive remnants of the Taliban, probably assisted by Al Queda terrorists, seem only capable of killing a number of civilians, as seen in the recent Kabul car bombing. The attempt on the life of Karzai was scary - but very poorly executed. In fact had the gunman shot Karzai dead it wouldn't have done one thing to bring the Taliban closer to regaining any power in Afghanistan (although other groups, other warlords may have profited). The alleged Taliban resistance to the US and Afghan forces has been weak and ineffectual. Here's a typical daily report:

"There were a few, unsuccessful attempts to attack US forces yesterday, Afghan and US military officials said. A rocket landed about 54 yards from a Special Forces firebase in Lawara, about 20 miles east of Orgun. Two rockets and a mortar were reportedly fired at the US base at the Khost airfield, according to the provincial governor and US military officials. A gunman fired at a guard tower at the Bagram air base outside Kabul. US soldiers returned fire, wounding the gunman, who escaped and was then taken to a hospital by local Afghans."

There's absolutely no danger of the Taliban ever regaining power in Afganistan. They're finished. If enough of them were even to gather in one place long enough to be detected the US would instantly bomb the crap out of them. There will of course be instability, chaos, and violence over the extended period necessary for the new Afghan government and military to slowly but surely expand its power and control over the entire country, one step at a time. (hard to criticize the effort and progress in this endeavor - who's ever succeeded at this task before in history?) The real threat is posed by provincial warlords who aren't too keen on bowing to Kabul's authority. But when the new Afghan Army is strong enough to deal with these pests, it will.