In fact, there’s zero hand wringing, because DoD is not planning on changing their policy.
I hope you would agree, though, that any BAC beyond trace amounts in someone showing up for duty is problematic.
Nope, completely in agreement - and let's be honest you can call someone unfit for duty for being hung over, BAC is just a nice to have after the fact.
DOD won't have to consider changing their policy unless federal legalization happens.
I don't think that's unrealistic in our lifetimes.
To cut to the chase, there seems to be a mix between whether we really need to on the spot measurement of THC levels to deal with the issue of abuse of a legal substance similar to alcohol/BAC (we sort of don't - within DOD you can subjectively make that determination and go straight to NJP) and identifying habitual illicit drug use (if MJ is federally legalized then authorized within DOD, the issue of varying THC levels/response to routine drug testing with chronic use becomes irrelevant).
There are mounds of scientific research on why the legal limit is set at 0.08. The vast majority of people show impairment operating a motor vehicle at that level, even if they don't show other signs of being drunk. There's even credible research to support lowering it to 0.02 - 0.05.
Sure. I don't disagree with the rationale or wherever the number is set. The point is they picked a certain number, and didn't worry too much about a number of outliers who may respond differently to the data in the studies.