not true. Unless you mean that you must be a registered voter to vote. Lots of people who are undeclared (U) or Nonpartisian (N) can vote in primaries. If you meant allegiance to the 4 recognized parties in Alaska (Independence Party, Libertarian Party, Democratic Party and Republican Party), that is a citizen's choice as well. Although you must be a registered Republican to choose the Republican ballot in the primary and also at the Presidential Preference Poll.