The Republicans opposed the Affordable Care Act when it was passed, and tried at least 50 times to repeal it after it became law. They told a whole rash of lies about it, and initially convinced many Americans it would be bad for the country. Their hope was that they could ride this issue into the 2014 election, and use it to seize even more control of Congress. But it hasn't worked out for them.
Many of us thought that the opposition to Obamacare would dissipate as people became more familiar with it, and saw the Republican claims were just not true -- and that is exactly what has happened. You may have noticed that GOP attempts to repeal Obamacare have stopped in Congress, and after winning their primaries, Republican candidates are staying pretty silent about the issue. That's because they have read the writing on the wall (i.e., the polls) and realized that promising to repeal Obamacare won't get them any votes with the general public -- and could actually cost them votes in the November general election.
The truth is that 12% of the public wants to keep Obamacare as it is, and another 47% want it to be fine-tuned, but not repealed. That makes 59% of the population that does NOT want Obamacare repealed, while only 36% still would like it repealed (and 5% don't know what to think). Those numbers make it pretty clear why Republicans are not campaigning on repeal anymore.
These numbers are from a new Rasmussen Poll -- done on August 30th and 31st of a random national sample of 1,000 adults, with a margin of error of 3 points.
I am opposed to the repeal of Obamacare -- but I also don't think that law went far enough in reforming our health care system. I think we need to go further -- all the way to a government-run single-payer health insurance system (sort of like Medicare for all). That would not only cover all American citizens with decent health insurance, but it would take the profit margin out of insurance and allow the government to negotiate with Big Pharma and health care providers to keep costs down (as other countries do).