Ok he didn't meet her before his campaign, and they only met because she was to be his VP.
They talked for an hour, which means he offered the slot to someone he didn't know before that day, and knew for only an hour.

Initially I thought his choice was a great move and would gain him a lot.
But as the dirt start floating to the top, imo she became more of a liablity.
By now I think he made a fatal mistake with Palin.