More troops in Afghanistan means asking those who serve to risk death. It means "collateral damage," civilians killed, and it may mean success.
When the war is a foreign insurgency, balancing human risks and possibility of success is a fundamental ethical dilemma for leaders.
Foreign wars can be won: Britain in Malaya, perhaps America in Iraq. Often they are lost: France in Algeria, America in Vietnam, Russia in Afghanistan.
In Science of War, O'Hanlon argues regarding success that, "There is a science of war. That's important..., not because it answers questions definitively, but because it at least constrains and grounds the debate in reality." For instance, you can calculate the troops needed to clear, rebuild, and hold a district.
O'Hanlon also notes that Sun Tzu and Clausewitz were "...mostly right about the nature of war, that it is mostly about human endeavor and enterprise and effort and courage and tactics and performance under stress...," that it is an art.
So, troop levels become artistic decisions constrained by science, which leads O'Hanlon to agree with General McChrystal that more troops are needed in Afghanistan. Do you agree?
However, this art and science may beg the question: In 2001, Afghanistan was a response to the threat of terrorism. Does threat still justify this war?
Some wars are necessary; some conflicts endure; sometimes peace breaks out. WWII, the Middle East, and Northern Ireland come to mind.
What do you think is in Afghanistan's future?