(I don't actually plan to submit a proposal along these lines any time soon; this is just an idea.)
Create a rule with power 3, titled "Security Groups": A Security Group is a certain type of entity. A Security Group with power 0 cannot exist; if such a Security Group somehow exists, it immediately ceases to exist. Every Security Group contains some number of entities as members. The collection of members of a Security Group is a substantive aspect of that Security Group. Create a rule with power 3, titled "Security Groups Control Mutability, Too": A rule that makes a change, action, or value (hereafter the controlling rule) controlled by a Security Group thereby makes it IMPOSSIBLE to perform that change or action, or to set or modify that value, except as allowed by an instrument which is a member of that Security Group, or by an instrument with power 3 or greater. As an exception, the above paragraph never prohibits an instrument from adding itself to a Security Group whose power is less than or equal to the power of the instrument. ---- An example of an intended use case: we might want to say that, say, proposals can only be created or modified through specific well-understood processes; and, in particular, proposals can't be arbitrarily messed with by any ol' rule with power 2.5. You could just say something like the following: "There is a Security Group called "Proposal" with power 3. Altering any substantive aspect of a proposal is controlled by the "Proposal" Security Group. A proposal CAN, as part of its effect, cause this Rule to add it to the "Proposal" Security Group." Then add all relevant rules to the "Proposal" Security Group. Now it's possible for a rule with power 1 to mess with proposals if it's in the Security Group, and a proposal with AI 1 can amend such a rule, but it's also impossible for a rule with power 2.5 to mess with proposals if it's not in the Security Group, and it has no way of letting itself in. —the Warrigal
