The Afghan government was given the option to take meaningful steps to apprehend the Al Qaeda leadership before NATO invaded. They chose not to, and in fact made public statements to defy NATO. So I don't think your analogy with Mexico holds up. Furthermore, if there is an analogy, it would be comparable to the US invading Colombia to kill Escobar. The difference, of course, being that we worked with the Colombian gov't to locate and kill him, and then we left. On a side note, I think the UN should have invaded Afghanistan well before 9/11. The U30 crowd may not remember them bombing ancient Buddhist shrines (UNESCO heritage sites), or imposing laws that imprisoned single women. The world was derelict in our duty to protect the meek and 9/11 was just one dramatic example of what can happen in such cases.