Hedgehog, to answer your question specifically, none of the three scenarios would scare me at all. I don't think Hillary would be qualified to be a Supreme Court judge, so I think that is the most far off base of the three. She seems like a very objective thinker, from her positions and explanations of topics, IMO, and probably would make a good judge of issues.
I think Obama as President is an important historical scenario, and I think the man himself is someone who would bring a standout demeanor, communication skills and intelligence/balance to the office - which to me is important and has been sadly lacking for the past few years.
And honestly, a McCain/Lieberman administration would not be something I would have a big problem with. I think Lieberman made a bad choice when deserting his party after losing his election, and think his policies to be pretty self-serving (Israel, etc.), but I consider both men to be adequate candidates for high office.
I know real objective thinking and posting is off base around here of late, so I apologize in advance for a non-bashing, non-threatening commentary.
