Leaving now would be spitting in the face of every person that has died in this war. The families of dead soilders have said that they want the military to stay, so their sons and fathers haven't died in vain. And if we stay, and fix this, they won't have.
Logical fallacy, killing more people wont change the fact that those people are already dead. Value is independent of the price paid.
To quote that joy of joys wikipedia:
Economists argue that sunk costs are not taken into account when making rational decisions. In the case of the movie ticket, the ticket-buyer can choose between the following two end results:
1. Having paid the price of the ticket and having suffered watching a movie that he does not want to see, or;
2. Having paid the price of the ticket and having used the time to do something more fun.
And the bit we want:
Loss aversion and the sunk cost fallacy:
Many people have strong misgivings about "wasting" resources. This is called "loss aversion". In the above example involving a non-refundable movie ticket, many people, for example, would feel obliged to go to the movie despite not really wanting to, because doing otherwise would be wasting the ticket price; they feel they passed the point of no return. This is sometimes called the sunk cost fallacy. Economists would label this behavior "irrational": it is inefficient because it misallocates resources by depending on information that is irrelevant to the decision being made. Colloquially, this is known as "throwing good money after bad"
The whole thing is just a small part of the entire Sunk Costs article so it is very focused on the economical aspect but it applies to things like the lives of soldiers as well as it applies to coins.
And no, there is overlap in fenrif's percentages you can't just add them all up to see how many people are affected..
That does not work just as well with the lives of soilders as money. Leaving now and having no one else die would be
wasting the lives of all the people that have died. Staying, and having hundereds more die would be
spending those lives to save the lives of thousands of people yet to come.
To put it in perspective, what if your father was a soilder, and he went to afganistan, and got killed fighting for those people, and then we decided to leave. Wouldn't you feel like shit, realizing that your dad died for no reason, that nothing will have come of his death? Even if you belive in your loss aversion theroy, you would still feel like shit.
The example above doesn't translate properly to lives. It specificly states "doing something more fun", meaning you still get the same or better benifit (fun), leaving now gives us an immediate benifit (no more soilders die), but many more people will die, and many more will be oppresed, and forced to live in horrible conditions.
And yeah, their conditions suck right now, but think of the conditions of the British, French, and Russians during both world wars, they were as bad as they are in Afganistan now, but now things are better. Right now were fighting a war, when that war is over things will be better. You're assuming that things can never get better, and they always can. We could have easily given up to the Nazis, our soilders would have stopped dieing, but the what would have happend? We'd be living in a place very much like Afganistan will be if we give up now.