The shift among the Democratic party's large swath in the ideological middle-- most Democrats in this poll, 57 percent, identify as moderate or conservative -- is driving an overall drop in party support for the legislation: Just 58 percent of Democrats now support the law, down from 68 percent last year and the lowest since the law was enacted in 2010. This broader drop mirrors tracking surveys by the non-partisan Kaiser Family Foundation and Fox News polls, both of which found Democratic support falling earlier this year.
Politically, the downward shift among moderate and conservative Democrats may be inconsequential. Senate Democrats have ignored more than three dozen House Republicans efforts to repeal the law, and even if they lost control of the chamber in the 2014 midterm elections Obama would surely veto any attempt to undo his signature legislative achievement.
But persistent skepticism of Obamacare continues to pose an obstacle to getting key parts of the law off the ground. The Obama administration is planning to exert enormous education efforts in the next 12 months to persuade uninsured Americans to sign up for new health insurance exchanges, and it's unclear how much political opposition will discourage people from participating.
On the other hand, launching health insurance exchanges for those who are uninsured offers an opportunity for the Obama administration to win over detractors through action rather than political argument, which has not been very effective. It may be the last best chance for Obama to win support for a law that has been stubbornly unpopular from the start.
Clement is a survey research analyst with Capital Insight, the independent polling group of Washington Post Media. Capital Insight pollster Jon Cohen contributed to this report.