Twisted Logic on Pakistan's Nukes

Someone help me understand this: the biggest danger in South/Central Asia is al Qaeda getting its hands on one or more of Pakistan's nuclear weapons. Al Qaeda's leadership and many of their fighters are currently in Pakistan. Therefore the argument is we should send 40,000 more troops to Afghanistan? I'm not sure I follow the logic chain. Assuming we failed and largely pulled out of Afghanistan, and assuming the Taliban (whose leaders are also primarily in Pakistan) re-take control of much of Afghanistan, and assuming the Taliban welcome al Qaeda back and provide them the oft-mentioned "safe haven" (and none of those assumptions are sure things by the way), they would then be MORE likely to attack Pakistan's nuclear facilities?

When the Taliban famously advanced into the Swat valley, within 90 miles of the capital Islamabad, I argued against the doom sayers, saying Pakistan was not about to collapse. Now the Pakistani military has largely driven the Taliban from Swat and is preparing for an offensive in South Waziristan, home to much of the Taliban leadership. Drone strikes have successfully taken out many leaders, including Baitullah Mehsud (leading to this lovely ditty). Pakistan was not about to collapse then, and is not about to collapse or give up its nuclear weapons now. Pakistan's nuclear weapons are safe, and should not be used as a bureaucratic pawn in the strategic debate. I'm all for a vigorous debate on goals and strategies, but let's apply a few sober standards of logic to this strategic conversation.