In trying to make up my own mind about who would make a better president, Clinton or Obama, I've been reading the news and visiting websites. (I can't bear to watch TV news except MacNeil/Lehrer, which "outs" me for the long-haired liberal I am) In the course of learning more about the personal lives and histories of the candidates, I reflected on their career choices based on my own experience working in a government political appointment. Knowing the art of compromise is an important aspect of the political career path.
Until you work in a political job, it is all theoretical about how you would handle tough choices. In order to get something accomplished, do you sometimes have to give up something or part of a principle important to you? It's easy to say, never, I'll never "sell out." But if you've had any political job, you know that "selling out" - i.e. giving up a principle you believe in, aka "compromise," can happen in many forms, and is not always a bad thing if you limit the damage to your beliefs and you accomplish something that's important to you. And you return to fight another day. Compromise ALWAYS happens in politics, which is one reason why we disdain it.
So in this Democratic war of idealism versus coolheaded (some say calculating) approach to handling some very tough future problems, I think the most realistic approach is to include both. We need hope, but also tempered by realism. It's an oxymoron, but there you go. That's what the political path is all about. If you're not prepared for moral ambiguity, don't go into politics.