The latest news on Mitchell, Harry
Control of House could hinge on rematches in 10 races.
Ties also seen in key senate races.
Party focuses on narrow field of competitive races, appears to be bracing for GOP wave.
Some Democrats see hope, thanks to federal dollars and projects being steered to home states.
Rep. Meek cinched Florida's Senate Democratic nomination by defeating political upstart Jeff Greene.
McCain and Murkowski were poised to win bitter primaries against tea-party-backed candidates.
GOP challenge to Sen. John McCain is one of the top contested races in Arizona's primary election.
Westerners who helped elect a raft of Democrats to the House and Senate now appear to be wavering.