For political junkies, June 6 has been circled on the political calendar for months. Eight states hold primary elections today. There are important races for gubernatorial nominations in California, Iowa and Alabama, a contested Senate primary in Montana and a number of competitive House primary battles. All in all, it's almost too much of a good thing. There are so many good races out there and not enough time to give each of them their due. In an attempt to bring readers the essential, need-to-know information about today's races, The Fix is providing the primer below. Remember: This is not...