If a significant terrorist leader or group is identified and located in Pakistan and there is a good chance to eliminate them, then it is justified for Obama to use a drone to do so. This should be reserved for only significant targets that are clearly identified however, as invading Pakistan's airspace and/or hitting a misidentified target have serious negative consequences.
I think we have a long enough history of our "friend" Pakistan having somebody we want located or in custody and suddenly "oh no they got away how could this happen?" If you're trying to be deceptive when your borders are a popular spot for dangerous people, then somebody needs to have an honest set of eyes there.
Obama should use drones in Pakistan because it's either that or we risk even more of our own men to go in and find take out the most wanted and detrimental terrorists acting out against our country. It is also a very efficient, reliable and easy way to get the needed work that needs to be done, done.
Obama should use drones in Pakistan to monitor terrorist activities. It is very important for the US to monitor these activities because the Pakistan government is unable to do so despite US help. In Pakistan, the terrorist bases should be destroy to protect American security to avoid another attacks like the 9/11.
All forms of military interference in the Middle East should come to an end. It is this form of imperialistic behavior that continues to justify the violence that our enemies use against us (Americans). The United States for far too long has been overriding international law by violating the sovereignty of other nations based on the pretense of "national security." I can assure you one thing, removing our troops from the Middle East will be the best possible way to ensure a long lasting peace. The usage of drones in Pakistan will not solve our issues, it will simply create more.
Although we may occasionally take out a "bad guy," these are cold and ruthless killing machines that also kill innocent people. The travesty is that, when they do kill civilians, all the US government does is reclassify those people as enemy combatants or insurgents. Drones also do not sit well with the people of the country we are attacking, so of course that will only perpetuate the cycle of terrorism.