Massachusetts: Not surprisingly, much of the battle for this open seat will be in the September 9 Democratic primary. The state party convention winnowed the candidate field down to three: Attorney General Martha Coakley, state Treasurer Steve Grossman and Donald Berwick, the former administrator of the Centers for Medicare/Medicaid Services. While Coakley is the frontrunner in the polls, she placed second at the convention behind Grossman. Berwick’s surprising strength at the convention makes him an interesting addition to the primary field. Again, Coakley is the frontrunner for the nomination, but the primary bears watching. On the Republican side, former Harvard Pilgrim CEO Charlie Baker is running again. He was the party’s nominee in 2010 and took 42 percent to 48 percent for Democratic Gov. Deval Patrick; independent Tim Cahill got 8 percent. Apart from running in a very blue state, Baker struggled to connect with voters. Strategists say that he will run a different campaign this time that focuses more on meeting voters than simply promoting policy proposals. The primary isn’t until September, which should give Baker ample time to

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