Ron, Some simple facts:
However RIPE itself only holds its own position and authority by dint of the charter which has been granted to it by IANA.
No. RIPE holds its own position and authority by the consent of the European Internet address using community.
And IANA in turn only holds its position and authority by dint of the charter which has been granted to it by ICANN.
No. IANA is a set of functions currently performed (depending on your point of view) by ICANN under RFC 2860 and RFC 7020 and/or via contract to the US Dept. of Commerce, NTIA.
Thus, in short, it appears to me that ICANN effectively sets the policy for everyone, and specifically for all five of the Regional Internet Registries, including RIPE.
No. All five RIR policies are defined by their respective communities, most assuredly NOT by ICANN. ICANN's role with respect to the RIRs is exclusively in relation to the establishment of new RIRs (RIPE existed prior to ICANN's creation) and the publication of IANA-related resource management policies that have reached consensus among all five RIRs. Regards, -drc