Yes, in that first sentence, I did mean "Pakistan", not "Afghanistan".

We were on a rampage then, and people were sensing "Pearl Harbor", no one wanted to get in our way. We were the sleeping giant itching for a fight, even the Iranians were cooperating with us back then.
Pakistan might certainly have played ball. With the US, fresh from 9/11 and in a righteous kick-ass mood pouring assets into Afghanistan and the fleet gathering offshore, the choice between forbidding us to move into a border area that was already a headache for them, and helping us clean it out once and for all would have been a very tempting one for them. Whether this would have made good political sense, either for the US or Pakistan, I concede is not so clear. But miltarily, it was doable. We're not talking mass troop movements here, just crossiing the border after OBM. Hell, we almost had him at Tora Bora. If Musharraf had chosen not to cooperate, it might have caused trouble, and perhaps it was indeed offered as a plan and rejected. But when Iraq happened, the momentum in Afghanistan certainly slowed down and started to reverse.

Capturing Bin Ladin later meant ground trrops, and lots of transport capability. Artillery would have been secondary, and armour practically useless in that terrain. It would not have required 130,000 ground troops, in fact, it's unlikely we could even supply a force that size in Afghanistan, which has no seaports or easy land access from the sea. But the fact that we are now spread too thin in Iraq is incontestable. Even the "surge" is considered unsustainable in the long run. We needed infantry, not a navy, to capture Bin Ladin, and Iraq was a drain that came at the wrong time.

As for the democrats opposing military action, they were quite ready to hop on board early in the war when passions were running high over 9/11 and the Taliban were scattering away with their tails between their legs. The democratic opposition, like my own, grew gradually and slowly as the effort in Afghanistan was abandoned and Iraq began to consume resources and attention and eventually, started to bog down.

You may have a point when you question whether or not Bin Ladin might have been captured early in the war. But there is no doubt in my or any one else's mind that if the effort lavished on Iraq had been even partially directed into Afghanistan we would now not be facing a daily growing reconstituted Taliban threat.

As for the decision to move into Iraq, the best assessment you're going to get from anyone not ideologically joined at the hip to the Bush Administration is "it may have seemed like a good idea at the time, but it was a colossal mistake." But even that could be forgiven, an even bigger error was not recognizing that blunder after it was obvious and continuing to pour resources and good will into it after it was clear it was a mistake. We could have recovered from Iraq. That's what really hurts.