(CNN) -- A federal appeals court in Atlanta was openly skeptical Wednesday that the sweeping health care reform law championed by President Barack Obama would survive constitutional scrutiny.
A three-judge panel heard arguments in a massive lawsuit brought by Florida and 25 other states.
The 11th Circuit Court of Appeals was the latest of three similar federal panels across the country to hear challenges by states and private groups to the Patient Protection and Affordable Care Act. Separate rulings from those courts in coming months will form the basis of a certain appeal to the Supreme Court, which could offer the final word on the landmark legislation, perhaps in time for the 2012 election year.
The main issue was the law's so-called individual mandate, the requirement that most Americans purchase health insurance by 2014 or face severe financial penalties. Lawyers for the states said forcing people to buy a product like health insurance is unconstitutional and unprecedented.
"If we uphold the individual mandate in this case, are there any limits on congressional power?" asked Judge Joel Dubina, who was named to the bench by President George H.W. Bush. His daughter is a first-term GOP congresswoman from Alabama, Rep. Martha Dubina Roby.
The two other judges who heard the nearly 2 1/2 hours of arguments -- Judges Frank Hull and Stanley Marcus -- were also concerned the law went too far in mandating that states expand various Medicare health coverage requirements. Both judges were appointed by President Bill Clinton.
The case, Florida v. U.S. Department of Health and Human Services, was moved up from District Court after a judge in January declared key provisions of the health care law unconstitutional.
Initial arguments refocused attention on the issue of "coercion." Basically, the 26 states are arguing that the requirement that states expand Medicaid coverage amounts to compulsion and coercion of the states, in violation of the 10th Amendment to the U.S. Constitution.
The judges also heard arguments on "severability" -- whether the determination that one provision of the law is unconstitutional invalidates the entire act. District Court Judge Robert Vinson, who heard the case in January, ruled that the unconstitutionality of one individual mandate voided the entire piece of legislation.
The appellate court heard arguments regarding the individual mandate as well, but focused much of their time and attention on the issue of coercion.
Paul Clement, who argued for the state of Florida, said after the hearing, "We were very gratified that the court ... was very interested in the coercion arguments, and the fact that this is the most coercive statute ever passed, that really limits the ability of states to make a decision or not."
Florida Attorney General Pam Bondi issued a statement congratulating Clement on his work.
"Our attorney ... did an excellent job," the statement said. "The federal government could not rebut our argument that the individual mandate is an unprecedented intrusion on individual liberty. ... I am encouraged by the judge's response to our arguments that the health care law's Medicaid expansion unconstitutionally coerces the states by forcing them to assume billions in uncompensated Medicaid costs."
Acting U.S. Solicitor General Neal Kumar Katyal presented the Department of Health and Human Services' case. He specifically addressed the individual mandate. Katyal said it was a tax and, therefore, constitutional.
Texas Attorney General Greg Abbott picked at Katyal's argument: "The lawyer for the Obama administration actually threw President Obama under the bus, because the Obama administration lawyer came out and said, 'This is a tax,' which is contrary to what President Obama promised, which is that he would not raise taxes on people."
Joining Florida in its challenge are Alabama, Alaska, Arizona, Colorado, Georgia, Idaho, Indiana, Iowa, Kansas, Louisiana, Maine, Michigan, Mississippi, Nebraska, Nevada, North Dakota, Ohio, Pennsylvania, South Carolina, South Dakota, Texas, Utah, Washington, Wisconsin and Wyoming.
Virginia and Oklahoma have filed separated challenges, along with other groups and individuals opposed to the law.
There are about 450 components to the health care law. Some will not go into effect for another two years, but some have already gone into effect.
The parts of the law currently being administered include small-business tax credits, federal grants and consumer protection measures.
The 6th Circuit Court of Appeals in Cincinnati heard arguments last week in another case related to the Health Care Act. The 4th Circuit in Richmond, Virginia, heard two challenges last month.
Judges in Florida and Virginia have found parts of the law unconstitutional in recent months, while courts in Michigan and Virginia have upheld provisions.
CNN's Kim Hutcherson and John Sepulvado contributed to this report.