Insulting nickname for Sarah Palin, Governor of Alaska, and Vice Presidential nominee for the Republican Party. So named for her lack of intelligence, her right wing radical views, and the fact that she is a complete and total drag on McCain's campaign for President. Like, a disaster...
The fact that the nickname rhymes is just a cool co-incidence.
Joe: Are you voting for McCain?
Bob: You crazy? I don't want the Disasta from Alaska as Vice President!! She's as dumb as a bag of hammers!!