Via WaPo:

Republicans have plenty of reasons to dislike Obamacare already, but they haven’t focused on one that could affect them in 2014 and beyond: anyone signing up for insurance under the Affordable Care Act will also have a chance to register to vote. […]

Could this give Democrats a political advantage? Potentially, since they stand to benefit the most from a surge in voter registration among those who currently lack insurance. By more than a 2 to 1 ratio, uninsured Americans supported Barack Obama over Republican Mitt Romney in a Washington Post-Kaiser Family Foundation poll last summer (62 to 27 percent). Obama led by a smaller eight-point margin among those who have health insurance. African Americans and Hispanics make up roughly half of the nation’s uninsured, a factor that explains much of the political divide.