Even in Kentucky, which championed the 2010 health care law by expanding Medicaid and running its own insurance marketplace, about half of poor people say they have heard little about the Affordable Care Act, according to a Harvard University study published Monday in Health Affairs.

Awareness of Obamacare was even lower in Arkansas and Texas—two states that have not embraced the law as warmly. The study — which surveyed nearly 3,000 low-income residents in the three states last December– found 55 percent of those Texans and 57 percent of those Arkansans had heard little or nothing about the law’s extension of health coverage. Arkansas expanded Medicaid eligibility to cover more people under the law, but the state legislature prohibited spending public money to promote that or the federal subsidies available to help people buy private Obamacare plans. Texas did not expand Medicaid and restricted private groups wanting to help people enroll in new insurance options.

Such assistance was critical to whether people completed the application for coverage process, the study found. In fact, enrollment assistance led to a nearly 10 percentage point increase in the probability of people getting coverage, the study found.

Not surprisingly, enrollment rates in Medicaid and the private health plans sold on the online Obamacare marketplace were higher in Kentucky, followed by Arkansas, with Texas having the lowest enrollment rate.  That was true even for applicants eligible for subsidized private coverage in all three states because their incomes fell between the federal poverty level (about $11,800 for an individual) and 138 percent of poverty (about $16,300). In Arkansas and Kentucky, people making up to 138 percent of the federal poverty level also had option to sign up for Medicaid. In Texas, they did not have that option.

The survey showed less than half of poor people in the three states said the law has helped them, though the rate of those saying they had been helped ranged from 40 percent in Kentucky, to 30 percent in Arkansas, down to 21 percent in Texas.

The findings confirmed what most experts have long presumed: State policies have a big impact not only on eligibility, but also on who chooses to apply for coverage and whether they successfully enroll.

That came as no surprise to enrollment workers in Arkansas and Texas.

Mimi Garcia, Texas state director for Enroll America, said her enrollment assisters have encountered people who thought the health law didn’t exist in their state because state leaders opposed it. “It’s definitely been an uphill battle,” competing with the governor and Republicans who constantly bash the law, she said.  Even if assisters get past that hurdle, explaining how insurance works to those who have never had it can be tricky. “This is all pretty intimidating,” she said.

Marquita Little, health policy director for Arkansas Advocates for Children and Families, said the study highlights just how important personal assistance is signing people up for Medicaid or subsidized coverage. Arkansas is exploring starting a state insurance exchange, though probably not until 2016 or 2017.

Few states have seen the impact of Obamacare more than Kentucky.

Since the fall of 2013, Medicaid enrollment in Kentucky has jumped by more than 500,000 people, or 88 percent, the highest increase in the country.  Another 109,000 people have enrolled in a private health plan through the state’s exchange. Since 2014, Kentucky’s uninsured rate has fallen from 20.4 to 9.8, the second largest decrease in the nation, according to latest Gallup poll. Arkansas has seen the biggest percentage drop in uninsured, from 22.5 percent to 11.4 percent.

While 49.5 percent of Kentucky’s poor said they heard little or nothing about the coverage options in the health care law, an earlier survey by the Foundation for a Healthy Kentucky found that only a third were unfamiliar with “Kynect,” the Kentucky exchange.

Benjamin Sommers, the study’s lead author and an assistant professor at the Harvard T.H. Chan School of Public Health, said the political fighting over the health law — which many predicted would end years ago — has hurt efforts to educate people about its benefits. “People are hearing conflicting messages,” he said.

Another factor in low awareness, he said, is that many poor people lead busy lives and don’t make health insurance a priority when they are healthy.

That lack of knowledge has implications because the biggest factor determining if people apply is not their political affiliation, nor education, but whether they are aware of the law, he said.

Among those who did not apply, the most common explanation was that they thought coverage cost too much, the study found. But in Arkansas and Kentucky, those surveyed could get Medicaid for free and in Texas those between the federal poverty level and 138 percent of the poverty level could get subsidies that would make the total cost nominal.  “People are worried about the cost when they don’t have to be,” Sommers said.