Before the votes were even counted, her fellow Democrats had compiled a list of reasons why Martha Coakley had struggled: anemic retail politics, a blind-eye to shifting momentum and an inexplicable appearance on a sports talk radio show that led her to misidentify a Red Sox star. There was truth to them all. But they also glossed over an obstacle that received far less attention in her losing bid for the Senate: a glass ceiling that remains almost impenetrable, even in the blue state of Massachusetts. To get an idea of how mind-bending the gender dynamics in this campaign were,...