I also think that in choosing her, he must have had some inkling that she would be the more popular one on the ticket, but he chose her anyway. I think he realized whoever he picked would be thrust into the political arena, possibly for years to come. He didn’t pick a runner up. He pick someone he knew would probably stand on his shoulders someday.
If he did nothing for our country other than give Palin a chance at the next Presidency, he would have already done quite a bit.
McCain was gutsy and shrewed, and had the confidence he could carry the day. Quite remarkable, when you think about it.
It appears that he's already standing on HER shoulders! But, I get your point, and I believe that this is tacitly understood by everyone, from McCain, down to the voters.
He already did plenty for our country. He’s an American hero.