You generally make a good point - but some of it still smacks of the left-wing delusion that if we had only elected the right man to the highest office, things would turn around. This is basically a modern version of the old myth of the "good tsar and bad boyars" that vented the frustrations of the Russian peasantry, or the myth of "speaking to the boss" to change things (espoused, inter alia, in Michael Moore's _Roger and Me_). They all belong to the genre of anthropomorphic simplifications of complex systemic relations - i.e. things are that way because powerful individual will them to be that way.
My position is that things would not be that much different here even if Karl Marx were elected president and Engels were his VP. It is so for two reasons: (1) The US is a very large and very complex society and no individual or a "kabal" can possibly control the social organism of such complexity, and (2) The US is also a democracy (very imperfect one, but still a democracy) not a monarchy, and the chief executive officer cannot just order things to happen - he needs to obtain a consensus of important power brokers. An the fact of the matter is that there are very few (if any) left-wing power brokers in this country. Most of the power brokers are conservative, or moderately liberal at best.
Therefore, supporting any candidate who takes an ideological grandstanding that is way of tune with the tenor of the power brokers in this country (both Nader and Kucinich do that in my opinion) is a religious wishful thinking and juvenile idealism - not serious politics.
Wojtek