Republican opposition to Medicaid expansion -- which is what I assume you're referring to -- served two main purposes. One, it weakened the impact of the ACA. Two, it eliminated a need for those states to dedicate additional dollars to their Medicaid programs.
We could argue the significance of the first point all day, so I won't bother. The second point is the one that deserves discussion from a pragmatic standpoint.
The federal government paid 100% of the costs for newly eligible Medicaid beneficiaries between 2014 and 2016. That number will gradually decrease to 90% by 2020, meaning the states will have to pay the remaining 10%. North Carolinians' federal tax dollars are subsidizing Medicaid in other states that chose to expand it. That's a bitter pill to swallow.
So what would be the impact of that 10% burden? North Carolina spends an average of
$5,356 per Medicaid enrollee each year. Medicaid expansion would add roughly
500,000 new enrollees in the state. That would mean an additional $2.68 billion in costs of which NC would pay $268 million (10%) at most. That represents a 6.1% increase in expenditures from
2016's budget of $4.4 billion. That's not insignificant.
The question then becomes whether it's a worthwhile investment. Studies have repeatedly shown the importance of preventative and chronic care in reducing healthcare costs. Consider the population who would most likely be affected by Medicaid expansion, and you're talking about people who will either delay care or forgo it entirely because they can't afford it. Then they end up presenting at the Emergency Room -- the most expensive site of care -- for an issue that could've been addressed much sooner. Same idea with cancer screenings -- breast cancer, colorectal cancer, etc. -- all of which are much easier and cheaper to treat with early detection. Same idea with chronic conditions like congestive heart failure, etc.
You also have to consider that higher numbers of uninsured patients hurts providers, who must provide more uncompensated care. That ends up hurting taxpayers because it means less state tax revenue, and it also drives up premiums for people who buy private insurance.
There's not necessarily a "right" answer to Medicaid expansion. You're guaranteed to spend more money without any guaranteed outcomes. Personally, though, I tend to lean towards the old adage that an ounce of prevention is worth a pound of cure. If you want to be a bleeding heart about it, it also means less human pain and suffering.