The current debate is shaping up as follows:
A: Palin isn't qualified to be president.
B: Why not?
A: Reasons x, y, & z.
B: Well, x might be a good reason, by y is pretty weak, and z is a ridiculous reason.
A: No it's not, it's a perfectly obvious good reason!
And so on.
This is all going to lead to actual deep things for me eventually, because I really am relooking at the questions of what a president does, how important each aspect is, and how much we can measure in advance. Good stuff. But I've just started and my head already hurst, so I'm going to make a sports analogy that seems quite illuminating to me, but probably has little actual value.
The presidency is one of those jobs that a lot of people have watched being performed and have strong opinions about, but few people have done it or anything much like it. I decided that NFL quarterback is a good equivalent. Commentators and fans all talk about what quarterbacks are good and why, and seem to know a lot about what play-calling and leadership skills the QB should be showing, but the number of people who have actually done it well is small. And many of those can't describe what they do all that well. Terry Bradshaw, for example, is entertaining but not enlightening on the subject.
John McCain and Joe Biden are both career backup quarterbacks. McCain has actually come in for an injured George Bush in the Iraq playoffs and done well, but neither has actually ever had much playing time.
Sarah Palin is a college QB from a mid-major who racked up some big numbers and brought her team to a surprise bowl win, but people worry about the level of competition she faced and whether she can adjust to the next level.
Barack Obama is a second year player from a big Division I school that had a mediocre record his senior year. He has never played in a big game. He had some great numbers against weak opponents at times, and looked pretty good in others. He's had a year to learn the system.
You're the coach. Who're you planning on starting this year? Ignore for the moment that Biden and Palin are both actually being considered for a backup position.
I think three of the four choices are defensible, but all four could plausibly be a disaster.
You can also have fun deciding which type of QB each of them is: scrambler, game-manager, high-touchdown/high-interception, plucky leader.