Because she's not qualified to be President.
This promises to be a close race.
Palin would be an old man's heartbeat away from the Presidency.
She has already shown that she doesn't know enough about matters of statecraft to be President. If we were a monarchy and she inherited the throne, the nobility would appoint a regent to do the real work, while she sat on the throne and wore the jewels.
She also reminds me very strongly of the people who took over my school board. brrrrr