The RACES in the FCC regulations is the designator of a DEFINED SERVICE (under the regulations). It is left to the sponsoring local or state government to administer it. That includes who can participate in the unit. Lets repeat that: it is the sponsoring government that determines who can be in the unit, not the FCC.
FCC regulations purposely do not direct HOW the AUTHORIZED functions are to be run. They do not restrict the service to Amateurs however much some may think that to be so. The RACES is an authorized SERVICE, which - IF and WHEN an FCC licensee operates on certain frequencies - it requires an Amateur Radio Service license. Otherwise, there is broad flexibility in what the unit participants may do on behalf of government so long as it isn't on Amateur frequencies.
Like other authorized services (law, fire, etc.) the FCC regulations ONLY apply as a REGULATION (contrasted to an AUTHORIZATION) when there is operation ON THE AMATEUR frequencies. ONLY THEN does it require an Amateur license, otherwise none is required to be part of that authorized function of local or state government. The regulations may not say that in so many words, but that is their overall effect from a legal perspective. If you do an unbiased survey of RACES units around the country you can discover ample evidence that there are those that have non-amateur participants.
The desire to limit the RACES to Amateur licensees is in itself a dilution of the service. It is the very reason that the RACES failed in some places; that and operators who said "I only use the radio, don't ask me to do anything else."
One of the obvious reasons for the Auxiliary Communications Service (ACS) is that it can include the RACES as part of its over-all umbrella. That means - notwithstanding the above explanation that RACES isn't limited to Amateurs - if the locals insist the RACES has to be so limited, then that limited RACES function could operate within the larger ACS.
Continues next week.
(This bulletin is in response to specific questions, not an attempt to tell one service or another how it must be run. It points out what we have learned over a long period of time.