The US military wants to develop "optionally manned" vehicles and ships so their crews won't be vulnerable to fast-spreading diseases.

Requiring fewer human operators does not raise any particular issue, except that such systems will be very expensive to develop and probably won't work reliably. However, designing them to operate without humans means they must either be remote-controlled — dependent on communications that will be slow and can be jammed — or autonomous killers.

The concept of "optionally manned" seems designed to smooth over that morally and practically important frontier and thus evade attention to crossing it.