A key thing to remember is that this is as much tribal as ideological.

It's true that insurgents, particularly with outside support, may not have to be popular per se, but if they really do have virtually zero local support they have problems.

In the largely Pashtun areas along the Af-Pak border, support for -- or at least tolerance of -- Taliban-type forces is certainly more than 1%. Within Afghanistan istelf, the Taliban is largely a Pashtun movement as well (the Durand Line, the British-created Af-Pak border, runs right through the middle of Pashtun territory).

In the rest of Pakistan, where the Punjabi and Sindi majorities vastly outnumber the Pashtuns, support is much lower. That's why the claim that the Taliban are only 100km from Islamabad is a bit less frightening than it sounds -- true, but the population changes a lot in that 100km. It's impossible to imagine a Pashtun-based isurgency gaining wide popular support from the Punjabi majority.

That being said, Pakistan is such a weak state that the Taliban are capable of terror operations anywhere in the country, and the pressure put on the central govt might cause it to crack on one of its preexisting lines of weakness. But it wont be because 100 million Punjabis rally around guys like Mullah Omar.