Final negotiations on merging the bills began in earnest Wednesday as congressional leaders spent more than eight hours behind closed doors at the White House using a process that bypasses a formal conference committee and cuts out Republican participation.

They dug into a series of sticky issues that separate the two versions of the bill passed by the House and the Senate — including abortion, access to health insurance by illegal immigrants, and how to pay for the sweeping legislation, which will insure an estimated 37 million Americans over the next decade.

A White House statement said they had made “significant progress in bridging the remaining gaps” between the bills.

Republicans have been howling about the process for nearly two weeks — House Minority Leader John Boehner, R-Ohio, called it “a breeding ground for more of the kickbacks” — but now congressional leaders are facing a growing mutiny within their own ranks.

Wednesday, Sen. Mark Udall, D-Colo., suggested the talks lacked transparency and called for televising final negotiations. Sen. Michael Bennet, D-Colo., also said final talks should be open to live cameras.

“I haven’t been in Washington long, but one thing I can tell you is this is one town that can use some fresh air, and some real transparency,” Bennet said. “The outcomes from the negotiations on the health care reform bill are far too important to be done behind closed doors.”

Those criticisms could create significant difficulties for efforts to finish the health care bill and move on to other legislation before the press of this year’s election cycle swamps Congress.

Media organizations and others have said televising final negotiations between the House and the Senate would be natural given the enormous potential impact of the legislation.

Instead, Democrats have created a process under which House and Senate leaders will hammer out key compromises, then send the retooled bill to both chambers.

Those negotiations are expected to go for days, if not weeks, and Democratic leaders have said a conference would only provide Republicans — only one of whom voted for the bills in either chamber — a new chance at obstruction.

“This non-conference conference was a bid to speed this up and bring it to an end. A conference committee seemed one more area where Republicans would attack the Democrats and liberals would get upset with leadership,” said Julian Zelizer, an expert on Congress at Princeton University.

“The problem is it looked bad. Republicans can use that to say health care is being rushed through and done behind closed door because Democrats want to hide something,” he said. “That’s why you’re seeing Democrats now getting nervous about the process as well.”

The House passed H.R. 3962 earlier this month, and Senate Democrats managed to beat back the threat of a Republican filibuster a few weeks ago, allowing the Senate to move forward with debate on the Patient Protection and Affordable Care Act, H.R. 3590. Both bills promise big reforms in the health-care and health-insurance industries. The Association for American Medical Colleges states that nearly 15 million people will be newly eligible for Medicaid and the Children’s Health Insurance Program under H.R. 3590, at an estimated cost of $374 billion over 10 years.

Fitzgerald says both bills contain huge holes regarding CHIP coverage for Mississippi children: “Right now, the fight over health-care reform in the House and Senate is all about abortion and the public option, but the children are getting lost in this discussion,” Fitzgerald said.

The issue, she said, centers on Mississippi’s unconventional requirement for CHIP eligibility.

Many states recently expanded their Medicaid program requirements to accept people who are a little further from the federal standard for poverty. Eleven states recently extended CHIP-eligible families’ income levels up to 200 percent of the federal poverty level, or higher. ($20,800 for an individual or $35,200 for a family of three).

But instead of expanding Medicaid, Mississippi set up a new health insurance program that contracts with private insurance companies. The states that expanded Medicaid will continue to receive federal support for those programs under both the bills under discussion in the House and Senate. But in Mississippi, all children and their families over 150 percent of the federal poverty level ($16,245 a year for an individual and $27,465 a year for a family of three) would go into an insurance exchange created by the House and Senate bills. The Senate bill plans to put CHIP-eligible kids in an exchange by the year 2019, while the House bill has them transferred by 2013.

Insurance exchanges do not promise the reliability of a government health program, Fitzgerald warns.

“Going into the exchange could require co-pays and premiums, the children would get lumped in with adults, and it’s not clear what requirements the insurance companies would have for their benefit packages,” she said.

There is also the question of permanence. Exchanges like the ones proposed by the House and Senate bills have not always been long-lasting. Texas, Florida, North Carolina and California all attempted—and failed—to create enduring insurance exchanges, primarily because private insurers tampered with the market.

A July report issued by the California HealthCare Foundation tried to pinpoint some of the factors that killed the California insurance exchange, which closed its doors in 2006. According to the report, the California exchange became too expensive when the clients it served became too costly. An exchange requires a certain number of healthy individuals to complement the more sickly participants of the exchange’s customer base; otherwise the cost of participation becomes too high for all participants.

But insurance companies in California lured healthy customers with lower premiums and steered the more sickly individuals into the exchange, creating a disproportionately expensive customer base.

“People involved in operations of the California exchange agreed that when there is competition for the same customers within and outside the exchange, the exchange is in ‘extreme peril’ of becoming a victim of adverse selection,” the report states. “If an exchange attracts a disproportionate share of higher risk individuals and groups as the California exchange did at various times, it cannot succeed.”

Fitzgerald said Mississippi’s eagerness to boot CHIP-eligible children from the program to keep down state costs is another factor complicating the new bills.

“Another problem is enrollment. We need enrollment in the exchanges to be simplified, because enrolling in state health programs have a history of being anything but simple in Mississippi,” Fitzgerald said, referencing a Medicaid policy championed by Republican Gov. Haley Barbour, which requires Medicaid recipients to meet Medicaid personnel “face-to-face” to be considered for program renewal.

CDF is working with its national office in trying to insert an amendment in the Senate bill though Democratic Sens. Robert Casey and Jay Rockefeller, which would keep all children up to 300 percent of the federal poverty level in the CHIP program until the new insurance exchange is thoroughly vetted.