The dramatic downsize underscores not only how consequential the health care law vote was but how quickly moderate Democrats have been eliminated on Capitol Hill. Even those who opposed the law had trouble surviving the highly partisan atmosphere it helped to create.
With the divide only more pronounced in 2014, the final four are trying to avoid a similar fate. Obamacare remains a volatile issue, and all still tout their “no” vote. Yet their vulnerability also reflects a more daunting and long-lasting problem for lawmakers who would occupy the middle ground.