Now, that the number of British soldiers killed in the Afghan War reached over 200, the people are asking, "Is the war winnable?" and "Is the war worth it?".
But the number of British soldiers killed in World War II was 382,700 (Wikipedia), and nobody asked these questions either at the time of that war, or even now, 70 years after its start. They even look back at that war with nostalgia, and call it "Britain's finest moment".
The other noticeable difference between the two wars, is the vocabulary. The phrases "mission", "exit strategy", "fighting the insurgency", and "fighting terror" were not part of the British World War II vocabulary.
And it is these differences in the vocabulary used and in the questions asked, that are clear signs that distinguish a war of aggression from a war of self-defence.
In World War II Britain was attacked and bombed, but not occupied, but in those countries of Europe that were occupied, it was the Germans, who had to fight "insurgencies" and "terror" of the resistance.
And it was the Germans, who started the war, who had a "mission". But, as they were defeated militarily, they were spared the efforts of "formulating an exit strategy".
In a war of self-defence, when a country is attacked and occupied by a foreign enemy, the questions "Is the war winnable?" and "Is the war worth it?" do not arise. The people are prepared to fight on until the aggressor is repelled and the occupier is driven out. And the more casualties are sustained by the attacked country, the greater is the desire of the attacked people to continue fighting the aggressors.
But, when a country sets out on a "mission" and attacks and occupies another country, then the questions "Is the war winnable?" and "Is the war worth it?" become of prime importance. The war is started in an atmosphere of "euphoria" and "national pride", "flower welcomes" from the "liberated" victims are forecast, and "cake-walk" victories are promised, and no doubts are expressed or questions asked. Then the attacked country is occupied, and a "victory" is proclaimed. But, as the "insurgency" develops, and "terror" mounts, and the body count of "our boys" keeps mounting, the questions of "winnability" and of "worthiness" begin to be asked, and the search for "exit strategies" begins. This is an established and predictable pattern of all wars of aggression and occupation.
And this is why the Afghans (the Taliban, or whoever else they be) are prepared to fight without questions being asked and without counting their casualties, until the aggressors are driven out. but the aggressors are counting their bodies, seeking ways to justify continuation of the war, and searching for an "exit strategy".
But a war of aggression is crime. and it is crime whether it is commited by "us" or by "them". so, the question to be asked is not, whether the war is "winnable", but, "Why the war criminals, who started a war of aggression, are still at large?".