The welcome final approval by the San Diego regional water board may not be the last hurdle that the proposed Carlsbad desalination plant must clear. Peter Douglas, executive director of the California Coastal Commission, wants one last stab at killing the project. It is not enough for the commissioners to restrain Douglas. They must replace him with an executive director who abides by the limits of his authority and honors the commissioners' decisions instead of undermining them. Poseidon's desalination plant, essential to San Diego's water future, is hardly the first project Douglas has assailed. It is, however, a prime example...