Do not prescribe a policy that the current group of officials cannot hope to implement because of who they are. I have had highly intelligent individuals -- including some with senior government experience -- sit in my office and lay out perfectly plausible policies that the current team, limited by time remaining in office, the pressure of competing and more urgent crises, and the all important mix of personalities, could never hope to put into effect.

Moreover, core beliefs and style constrain policy makers profoundly. So don't ask them to do something outside their range of psychological possibility by, for example, proposing cold-eyed realpolitik to a band of idealists or vice versa. There are no platonic ideal-type policies, valid no matter who is in charge. What may make sense for one administration may make no sense for another, not because of the external environment, but because of who has to execute the policy and live with its consequences.

High-quality commentary reaches audiences (including those overseas) who may not affect daily policy making, but whose opinions matter in subtler and longer-term ways. Well done, it sharpens a larger discourse -- and besides, it's more therapeutic than shouting at your television set. A prudent commentator should be modest in his aspirations, conscious of his limitations, and sparing with his exhortations.