I am just an observer and I only receive what international media publish about it. However, in my opinion the strategy of Mc Cain is pretty clear.
First of all, I must admit I prefer an Obama's victory...and than I think that USA is not ready for a black president (or a woman...) and I cannot take out of my mind an image of an ex-president in Texdas...ya, Mr.Kennedy.
During the primary elections, Obama weared himself out due to his confrontation with Ms. Hillary Clinton. Nevertheless, Republicans chose Mc Cain and he was watching the fight of his rival resting quietly on his sofa.
When Obama won, he always assumed the role of "I am the change". Mc Cain had to distance himself of George Bush and the starightness of Republican party. At this point, what could Mc Cain do?
After taking some time to think, and seeing how Obama chose Joseph Biden as vice-president (to contribute with his experience to the election campaign), Mc Cain introduced Sarah Palin.
Why Sarah Palin? Firstly because Sarah is she. It is a way to say that republican party is adapting to new role of women in our society. Besides, she is an unknown celebrity from Alaska. It means that will be really difficult to run her down with past mistakes. Thirdly, Obama is now attacked by Sarah, and he has to work hard to reply her. That's to say, Mc Cain is again sitting quietly on their sofa watching how Obama is arguing with Sarah without wearing himself out.
This crappy strategy could get that Mr.Potato sit on the presidential chair in the future...hope I am wrong