She didn’t go rogue, she was known to be a conservative- I am sure he chose her to throw a bone to conservatives voters that he knew were pretty cool to his Maverick actions of cozying up to the dims.
The issue was he underestimated Palin and her appeal, he also underestimated how many conservative voters there were. He meant to have her as a token to conservatives, but she took off like a rock star- she was just being herself she was not trying to upstage him. She was doing her best to get him elected.
He hired her under false pretenses and then threw her under the bus as fast as he could. The thing is, she was just a representative of conservatives- it was really we the people he threw under the bus. He had a nasty habit of doing that.
His campaign shtick every time he ran for office was to run as a conservative through and through, then when elected he scooted over to the dim side. He intended to do the same with his run for President; run as a conservative when he sure didn’t mean it. The thing is Palin did mean it.
She started believing her own headlines and broke from McCain on some topics.