The key domestic policy fight of 2017 will be over Obamacare. If it is repealed, then the centerpiece of the Obama presidency will lie in ruins. If not, then President Obama will have been what he set out to be: a sort of Reagan of the left—a transformative president who will have profoundly changed the direction of the country.
If Donald Trump is the Republican nominee, he won't win—or even wage—a fight to repeal Obama's namesake. Trump has declared during this campaign that "single payer" heath care "works incredibly well" in Scotland. He has repeatedly indicated that, despite our nearly $20 trillion national debt, he has no real interest in tackling the entitlement spending that is bankrupting us. And when asked a few weeks ago to give his "opinion" on what "the top three functions of the United States government" are, he said one of them is "health care."
This is not a man who intends to repeal Obamacare. Sure, Trump checks the rhetorical box in saying the opposite, knowing that to do otherwise would be to commit political suicide in a Republican primary. But in addition to his general enthusiasm for government monopolies over health care abroad, disdain for entitlement reform, and belief that the provision of health care is one of the federal government's three core functions, Trump's campaign has indicated even more specifically why repeal would be a pipe dream under a Trump presidency.
First, just a few weeks ago, Trump said, "I'm not going to cut Medicare or Medicaid," which means he wouldn't roll back the huge Obamacare Medicaid expansion that John Kasich and others chose to implement. Indeed, the framework of Trump's skeletal Obamacare alternative suggests he would increase Medicaid coverage even beyond Obamacare's already bloated levels. The Congressional Budget Office projects that more than $1 trillion of the $1.9 trillion gross cost of Obamacare over the next decade will come from its Medicaid expansion (see Table 3). So if Trump won't cut Medicaid spending, that means he wouldn't repeal more than half of Obamacare (at least in terms of dollar values).
Second, Trump has repeatedly said he wouldn't repeal Obamacare's preexisting-conditions mandate. This mandate undermines the very notion of insurance, which dates back at least to the Renaissance—namely, that one must buy insurance before the thing happens that one is insuring against. (This mandate is really two mandates in one: automatically approved insurance ("guaranteed issue") to sick people at the same price as health people ("community rating").) This mandate is a—probably the—key reason why Obamacare is causing premiums to spike.