OK.
I was a COR (Contracting Officer Representative) for a few months when I was an Engineer officer in VN back in 1970/71.
In all but the smallest bases, most of the hard work was done by locals either directly hired by the military (or small groups of GIs) or through contractors. The contractors usually had Americans in the higher level jobs. The next layer down were the TCNs (Third Country Nationals -- Korean & Phillipine in VN), and then locals.
The contract I partly "supervised" was for AC power distribution to several medium sized bases. I read the actual contract and it was a "Cost Plus" contract with an incentive which was dependent upon the rating given by the several CORs.
In my office and a nearby office we had contracting officers and CORs for all kinds of activities from road construction to water production to garbage disposal to fire fighting. In general the contracts (I believe/hope) were awarded on the basis of: 1) which "management team" would likely do the best job; and 2) which one worked the cheapest. Since it was definitely "cost plus" #2 was close to "down in the noise." We in the military were there for our year of duty. Many officers were given two completely different assignments within that year. The contractor folks (and a handful of US Government employees) provided much of the continuity.
Even within the major bases the Engineers had small units (usually call ____ detachment) which comprised kids who had all kids of civilian skills. In one case, a small building burned down and our "detachment" rebuilt it within a week.
The contractors may have traveled on the roads betwen the bases but they NEVER worked in fire bases or in bases that were in the middle of a continuing battle. If "engineering services" were required in these places, engineer troops and engineer officers did the job.
Our Hq (the "District Engineer") provided fire trucks to protect aircraft landing at KheSahn and a nearby refuel and rearm point in 1971. When a joint RVN/USA command post was set up, I took a kid with me to "wire the lights" as the general's Hq staff didn't include any "working" engineers.
The civilians made a lot of money for that time. But many/most of them had already served in the military including combat tours.
The US Army used a lot of civilain contractors during the "Indian Wars." The tales of their corrumption are manifest. BUT the US won the Indian Wars using an all volunteer army and without a draft.
Like it or not the military use of contractors is a good idea.
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