Check out this little nugget from Davidson in his comment to the Re-Proposal capital rule:
"CONCEPTUAL FLAWS OF THE RE-PROPOSED RULE The proposed rule appears to be based on three flawed concepts. First, it seems that FHFA believes that the Enterprises function like banks and should have bank-like capital. Second, that private capital can fulfill its countercyclical role within the housing finance system without government support. Third, that adding on buffers and minimums produces a better capital rule. Let us take each in turn."