LINCOLN, Neb. (AP) - The Republican governor repeated an earlier warning that he will oppose any efforts to extend Medicaid coverage in the wake of the U.S. Supreme Court's ruling on the federal health care law.

Heineman is one of at least six Republican governors who have promised to defy a provision of the federal health care overhaul that would expand Medicaid, a government-run health benefit program for low-income adults and the disabled. The law is one of President Barack Obama's crowning achievements as he runs for re-election.

The high court upheld most of the law last month, including a requirement that states create online marketplaces for people to comparison shop for health insurance. But the court ruled that the federal government cannot penalize states that defy the Medicaid expansion provision by withholding Medicaid funding it already gives to states, which amounts to a significant portion of their budgets.

"The bottom line is the unfunded Medicaid expansion will ultimately cost the State of Nebraska hundreds of millions of dollars," Heineman said in the open letter to lawmakers. "Furthermore, the federal government has a history of not fulfilling their financial commitment."

The meeting was organized by Sen. Jeremy Nordquist, an Omaha Democrat who supports the health care law, and co-sponsored by Republican Sens. Kathy Campbell of Lincoln and Mike Gloor of Grand Island, who lead the Legislature's Health and Human Services Committee.

Nordquist, a frequent critic of the governor, said his office invited both supporters of the health care law and stakeholders who likely opposed it. The meeting set for Thursday will include doctors, hospital administrators, consumer groups and insurance industry representatives.

Nordquist said the state's Medicaid director, Vivianne Chaumont, who is a member of Heineman's cabinet, previously confirmed in an email that she was planning to attend. According to a meeting agenda, she was expected to provide an update of the state's efforts to enact requirements of the health care law.

"It's extremely disappointing that Governor Heineman and his administration won't engage in a serious public dialogue in our state," Nordquist said Wednesday. "This is a bipartisan meeting of all key stakeholders about how we should move forward."

Nordquist pointed to U.S. census data that show Nebraska's rate of uninsured increased from 9.8 percent when Heineman took office in 2005 to 13.3 percent this year. He also cited statistics from the Commonwealth Fund, a private health care foundation, that show premium costs in Nebraska increased by 42 percent for single coverage and 45 percent for family coverage between 2003 and 2010.

The meeting was scheduled one week before an official legislative briefing with the Nebraska Department of Insurance, which is preparing the state to comply with the law. Department administrators have said they are designing a state-run health exchange to help Nebraskans comparison shop, but have complained about a lack of specific guidance from the federal government.

A U.S. Department of Health and Human Services official who is scheduled to speak at the Thursday meeting said he planned to pitch the benefits of the health care law.

"This was a hard-fought, very emotional battle over health care, and understandably so," said Jay Angoff, a regional director for the U.S. Department of Human Services in Kansas City, Mo. "But I think once people have an opportunity to step back and actually look at the numbers, they'll see what a terrific value it is - particularly for states that have not covered a lot of people under Medicaid."

The health care law required states to expand their Medicaid coverage to adults who make up to 133 percent of federal poverty levels, starting in 2014. A report commissioned by the Nebraska Department of Health and Human Services estimated that the Medicaid expansion would require coverage for an additional 108,000 to 145,000 residents. Most people who enroll would likely qualify for taxpayer-financed subsidies.

Omaha Sen. Beau McCoy, a Republican who sits on the Banking, Commerce and Insurance Committee, said only 12 of the Legislature's 49 lawmakers were invited to attend the meeting.

"I am disappointed that a small group of my fellow senators have chosen to meet tomorrow behind closed doors with a small group of advocates who were hand-picked to discuss the future of health care for all Nebraskans," McCoy said.

Heineman said in his letter that expanding Medicaid could force a tax increase or drain money from K-12 education, a network of small state colleges, and the University of Nebraska. He said expanding Medicaid would also add to the state's projected shortfall, which, according to the Legislative Fiscal office, is projected at $619.7 million for the upcoming two-year budget.

Heineman pointed to a University of Nebraska report that showed state aid for Medicaid increasing nearly 1,300 percent between 1984 and 2013. State aid for the university increased by 215 percent in that period, according to the report.

"My position is very clear - Nebraska can't afford an unfunded Medicaid expansion," Heineman said.

(Copyright 2012 by The Associated Press.  All Rights Reserved.)