Voters in Alaska, Arizona, Florida, Oklahoma and Vermont head to the polls today to vote in state primaries. Republican Senators John McCain of Arizona and Lisa Murkowski of Alaska are both expected to survive challenges from tea party-endorsed candidates. Some of the day’s closest races may be in Florida, where the Democratic Senate primary pits Congressman Kendrick Meek against billionaire real estate investor Jeff Greene. In the Florida Republican gubernatorial primary, State Attorney General Bill McCollum is battling former healthcare executive Rick Scott, who has spent almost $39 million of his own money on the campaign.