... In the last two weeks we've found Palin up 1 point in Texas, up 1 point in Nebraska, and down 8 points in South Dakota. What those numbers indicate is that she would only really be safe in states that Republicans won by at least 20 points in 2008. And there weren't very many of those. It's becoming clearer and clearer that a Palin nomination would be Goldwater redux for the GOP. ...More information about the 1964 election, which pitted Barry Goldwater against Lyndon Johnson, can be found in "Sarah Palin to take our country back ... to 1964. It'll be deja vu all over, again!"
TPM's "Poll: Palin Nomination Could Turn SD, NE Dem For First Time Since 1964" has some analysis of PPP's poll, as well as an interesting chart that shows how Palin's favorability began declining (from an already low level) in mid-October of last year.