A worthy objective but, for the reasons cited, unlikely to come to pass.
Perhaps, (only slightly) more realistically, the military should be taken out of party politics altogether by establishing a multi-party agreement a) that the armed forces cannot be subject to every short term whim of whichever party happens to be in power and b), therefore, the armed forces strategy, objectives, budget and equipment will be agreed on a cross party basis which will maintain oversight but which can only review and change at fixed intervals and then only with a significant majority of all parties so agreeing. If this can allied to a mechanism whereby the military exercise greater direct control over e.g. procurement to ensure less "spec creep" and fewer cost overruns, so much the better.