Support has grown for a ballot initiative seeking to fully expand Medicaid and provide health care to roughly 150,000 low-income Utahns, according to a new Salt Lake Tribune-Hinckley Institute of Politics poll.

The poll shows 59 percent of Utah voters favor Proposition 3, up from 54 percent in a similar survey conducted in June. The share of voters opposing the initiative fell slightly from 35 percent to 33 percent between the two polls.

“This is fantastic,” Prop 3 campaign manager RyLee Curtis said. “We’re reaching the people we need to reach, and our message is resonating with them.”

If approved by voters in November, Prop 3 would combine roughly $90 million — through a state sales tax increase of 0.15 percent — with $800 million in federal funding to provide medical coverage to Utah’s poor. Utah lawmakers approved a partial Medicaid expansion plan earlier this year, which relies on work requirements and increased federal funding to cover a smaller population of Utahns without raising state taxes.

The Legislature’s plan requires approval from the federal government — which has not yet granted or denied the state’s application — because it falls short of the technical requirements of the Affordable Care Act, or Obamacare.

(Christopher Cherrington | The Salt Lake Tribune)

The new poll was conducted by the Hinckley Institute between Oct. 3 and 9. It included responses from 607 registered Utah voters and has a margin of error of plus or minus 4 percentage points.

One survey participant was Thom Harrison, a Salt Lake City resident who said he initially opposed full Medicaid expansion but now plans to vote in favor of Prop 3.

“There are individuals who, because of their circumstances, are not able to provide medical care or medical help for themselves,” Harrison said. “I think it’s appropriate that we assist them in this.”

Harrison said he’s reluctant to back a tax increase. But in the case of Medicaid expansion, he said, the personal cost is outweighed by the potential to help others.

“There are people who need these services,” he said, “and the only way they’re going to receive them is with an increase in our taxes.”

Among the groups opposed to Prop 3 is the Utah chapter of Americans for Prosperity. State director Heather Williamson said her team will continue making thousands of calls each week to talk to voters about what full Medicaid expansion and another proposed tax increase on the ballot mean for the state.

“Utahns are compassionate, and we want to help people,” Williamson said. “We are confident that once Utahns learn that Proposition 3 will harm Utah’s most vulnerable and raise our taxes, they’ll see why they should vote no.”

Williamson’s group hosted a news conference Wednesday in the state Capitol Rotunda featuring a dozen Republican lawmakers opposed to full Medicaid expansion. House Speaker Greg Hughes, R-Draper, said expansion “comes at a price” to other state programs, and Sen. Jacob Anderegg, R-Lehi, said he’s prepared to sponsor a repeal of Prop 3 if it passes in November.

“With the public vote, I don’t think that’s sacrosanct,” Anderegg said. “If we don’t [repeal Prop 3] and the numbers turn out where we think they are, I don’t know how we’re going to fund it.”

But Rep. Ray Ward, R-Bountiful, disagreed with his colleagues and said he supports Prop 3. Budget challenges will exist with or without full expansion, said Ward, who also works as a physician, and no state that already expanded Medicaid has reversed that decision.

“Other states have figured out a way to make this work," Ward said. “Their people are benefiting. And we can figure out a way to make this work.”

Curtis said the Prop 3 campaign is encountering significant support as it discusses Medicaid expansion with voters. By failing to expand Medicaid under Obamacare, she said, the state has experienced a coverage “gap," which leaves many low-income Utahns struggling without adequate health care.

“A lot of people know somebody who is in this coverage gap,” Curtis said. “They’re thinking about them as they go to vote this November.”

She said she expects critics to be won over in time if the initiative passes. Most full-expansion states have seen positive results, she said, including decreased costs to state budgets as residents are able to obtain preventive and routine medical care.