When it comes to Berkley, Warren, Baldwin and incumbents like Sens. Claire McCaskill, D-Mo., and Debbie Stabenow, D-Mich., there is either no active Democratic primary, or a uncompetitive one with only nominal contenders comprising the rest of the field. One more interesting race is Hawaii, where there is an active primary. EMILY's List is backing Rep. Mazie Hirono, as is the state's Democratic establishment. National Democrats have also been protective of her candidacy. She's opposed by former Rep. Ed Case, a more moderate Democrat who has little establishment support and has historically proven to be something of a thorn in the side of the state's two long-serving Democratic senators.