Today is primary day in some key states for independent voters: Pennsylvania, Kentucky and Arkansas. Lots of media including this one from Liz Halloran at NPR talking about the anti-incumbent mood.
Pennsylvania primaries (thanks to FairVote for these definitions) are closed (winners in 2008 2343 Clinton, McCain in the primary; November: Obama), meaning that only registered Dems or Repubs can vote in that party’s primary. If you’re an independent, you’re flat outa luck. See Independent Pennsylvanians for redress!
Kentucky (Closed primaries: Clinton, McCain in primaries 2008; November: McCain) Voters of any affiliation may vote for the slate of any party (which seems to mean that independents can vote but can only vote in the party primary that they choose for that election, according to FairVote.) You might want to contact at Michael Lewis on Facebook or at Independent Kentucky.
Arkansas primaries are open except for runoff elections. Voters went for Clinton and Huckabee in the primary and for McCain in the general in 2008.
For more resources, see the Open Primaries page on The Hankster!