Expanding Medicaid under the health reform law Obamacare is still very much a third rail in about 20 states — 21 if you count Kentucky where the new governor has pledged to transform their program.

But in some of these states buying private insurance for people who are newly eligible – the so-called “private option” – is considered more politically viable than simply expanding traditional Medicaid.

Harvard’s Dr. Ben Sommers and his team conducted a head-to-head comparison between Arkansas’s private expansion and Kentucky’s public one.

As they publish in the journal Health Affairs, the researchers found both states significantly reduced rates of the uninsured and made healthcare more affordable.

“This provides pretty strong evidence, either private or public expansion of coverage is going to have impacts for people to get the care they need,” said Sommers.

These results could build up some “private option” momentum.

But the Arkansas Center for Health Improvement’s Craig Wilson questioned if this paper is enough to change hearts and minds.

“When you are looking at a state budget overall it’s about tradeoffs and it’s about stakeholders,” he said.

Wilson noted the cost of Medicaid programs remains one of lawmakers’ top concerns.

He said if and when a study shows the private option – or some other approach – can save money, then he thinks other states may start coming around.