John McCain’s campaign has sent out a press release that includes a copy of Sarah Palin’s voter registration in early 1982, shortly after she turned 18 on February 11, 1982. She registered “Republican.” However, the Alaskan Independence Party was not a qualified party at that time, and it was not listed as a choice on voter registration records. It won a lawsuit on March 4, 1983, called Vogler v Miller. The decision, from the Alaska Supreme Court, struck down the old Alaska definition of “political party” (a group that had polled 10% for Governor). The state then recognized the Alaskan Independence Party and began letting voters register into it.
It is not known if Palin later changed her registration from “Republican” to “Alaskan Independence”. Old-time leaders of the Alaskan Independence Party say she was a member before 1996.