The problem with situations like this, is that emotive language gets used, and more importantly, remembered.
Even phrases like 'mission' and 'getting the job done (a favourite of Mr Bush's) are evocative, because they beg questions - who created this 'mission', what is 'the job' and who exactly gave it to you?
I appreciate that Mr Cameron can hardly turn up and say - we are basically propping up a puppet government which will collapse when we leave, returning life here to the way it has been for the last eight hundred years, regardless of the obscene costs in terms of finance and lives.
As far as halting the opium crop - this year's crop is a record, and half of Afghanistan's opium crop is grown in Helmand, where the troops are, so it's hard to put a positive spin on that part of 'the mission'.
History will record that Britain and America tried and failed to subjugate the Afghan people to its way of thinking, and that Blair, Bush and Cameron were egotists with no concept of what they were doing.
I wonder how they sleep.