Not sure how much of a loss he will be to Defence. His resignation letter is a mixed bag of jumping on the public opinion bandwagon (how much longer will the public accept further losses) and shear wishful thinking (Defence sealing the last Liabour win, the next election being Liabour's for the taking).
But his point about the public not accepting further losses without good reason is an important point for me. It is indicative of how we as a country have become afraid to take risk and accept loss during military operations. Military commanders are now fighting with one hand tied behind their backs, constrained by the politicians' desire to fight a clean clinical campaign - something that will never happen in a grubby COIN campaign.
And much of this political desire has less to do with a genuince concern for the military and more to do with squeezing every last vote they can out of the public. Unfortunately, the vast majority of the country probably has little idea about Afghanistan, what we are doing there, the relevance of UK plc's approach, informed debate over resource and troop numbers and importantly the risk associated with military operations. Most of the public unfortunately take their lead from the tabloids, hunting for ratings and column inches, rather than informing accurately.
We need to get back to military operations being run by apolitical military commanders. They know what needs to be done, the best way of achieving it based on years of experience and guidance from within their Staffs, and understand the risks associated with it. They should own the risk, not the politicians. Public opinion should not be influencing the conduct of military operations.