Republicans are claiming to support, and re-enact, all the things that people like. Specifically:
We will make it illegal for an insurance company to deny coverage to someone with prior coverage on the basis of a pre-existing condition, eliminate annual and lifetime spending caps, and prevent insurers from dropping your coverage just because you get sick.Of course, the Patient Protection and Affordable Care Act of 2010 already does all those things, and those are the parts of the act that people like and support. What the Republicans want to get rid of are what are referred to as the "burdensome mandates," such as the requirement that all but the smallest businesses provide health insurance for employees, and the "individual mandate" that requires individuals not covered by employer-provided insurance to get health insurance or pay a special tax.
The reason that Republicans won't be able to repeal those parts of the act is that those are the parts of the act that the insurance industry likes. Requiring insurers to provide insurance to sick people without requiring healthy people to buy insurance is a prescription for economic disaster, because there would be nothing to stop healthy people from dropping their coverage until after they get sick. So insurers would have to provide the same (or greater) levels of benefits while the number of insureds shrinks, which would cause premiums to skyrocket.
And Republicans know this, which is why the "Pledge" is so specific about the parts of the act that they would want to keep and so vague about exactly what would be repealed. They know that, if they come right out and say that they are going to repeal the employer and individual mandates, they will be (or at least should be) ridiculed for proposing a completely unworkable system.
So if the Republicans actually try to repeal health care reform with actual legislation, they will be caught between a rock and a hard place. If they repeal the entire health care reform act without providing patient protection they will anger voters, but if they repeal the employer and individual mandates and leave the patient protections in place they will anger (if not bankrupt) some of the biggest contributors.
So it's pretty safe to say that there's going to be lots of rhetoric, but not much actual repeal.