Wednesday, Feb. 2, 2011 - With Monday's ruling by a federal judge that the healthcare reform law is unconstitutional, legal experts foresee a showdown in the Supreme Court, where the outcome could go either way.

Judge Roger Vinson, of the U.S. District Court for the Northern District of Florida, in Pensacola, on Monday ruled that the healthcare reform law is unconstitutional, siding with the 26 states that sued to block enforcement of the Affordable Care Act (ACA).

That makes four total rulings on the law: two that upheld the law, one that struck down the individual mandate portion of the law, and Monday's decision, which struck down the law in its entirety. Another 12 courts have dismissed the case.

"All of these cases are merely station stops on the way to the Supreme Court," Dr. Daniel Blumenthal, a community health professor at Morehouse School of Medicine in Atlanta, told ABC News/MedPage Today in an e-mail.

The ruling by Vinson is the harshest legal action yet against the ACA because, unlike the recent decision by a Virginia judge stating that the individual mandate portion of the ACA violates the Constitution, Vinson ruled the entire law "void" because the individual mandate provision can't be separated out from the rest of the law.

The individual mandate -- which requires everyone to buy insurance by 2014 or else pay a penalty -- exceeds Congress' authority under the Commerce Clause of the Constitution, which regulates interstate commerce, Vinson wrote in his decision.

Vinson agreed with the states involved in the lawsuit that the government cannot force individuals to participate in the stream of commerce -- in this case, the health insurance market.

The federal government responded that at some point, every U.S. citizen will seek medical care, and if that person chooses to not have insurance, the cost of his or her medical care is passed on to those with insurance. Thus, a choice to not participate in the commerce of healthcare doesn't actually exist.

Many legal and health policy experts say the Florida case is the most likely of the reform cases to make its way to the Supreme Court.

That process, however, may take a year or longer, several lawyers told MedPage Today. Generally, the Supreme Court waits until several appeals courts have ruled prior to taking up a case, which could put it on the Court's calendar for early fall of 2012, said Peter Leibold, CEO of American Health Lawyers Association.

Also, the individual mandate doesn't go into effect until 2014, which may be an excuse for the high court to delay consideration of the case, said Miles Zaremski, a Northbrook, Ill. attorney and past president of the American College of Legal Medicine.

When the Supreme Court does take it up, Zaremski guessed that Associate Justices Clarence Thomas and Antonin Scalia will likely feel that the individual mandate is not commercial activity that affects interstate commerce. Justice John Roberts and Associate Justice Samuel Alito, Jr., are also thought to be likely to decide the ACA violates the Constitution, which would put four justices on the side of repealing the ACA.

Meanwhile, Associate Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor, and Elena Kagan are considered likely to vote in support of the ACA, predicted Kermit Roosevelt, a Constitutional law professor at the University of Pennsylvania.

Associate Justice Anthony Kennedy may be the swing vote, Zaremski said.

Roosevelt guessed Kennedy would side with those voting to uphold the law, and that, ultimately, the ACA would not be struck down.

However, Blumenthal said that because five justices were appointed by Republican presidents, the vote is likely to be 5-4 in favor of striking down the law.

The legal battle over the ACA will be a nail-biter, because both sides have strong arguments, said Zaremski.

"You can make really convincing arguments on either side and be justified," he said.

Leibold said the outcome will depend on what each justice believes the case is about.

"It really depends on how well the advocates can persuade the justices that the story they're telling is the right story," he said.

One story is that the government is forcing people to purchase a product that they don't want to buy; the other story is that the government is simply trying to make sense of a system that is already highly federalized, Leibold said.

"You just never know," he said. "You can create believable stories each way."

Roosevelt said the Supreme Court's decision might be motivated more by politics than a straight Constitutional interpretation.

"A judge's decision will be affected by his or her ideology," he said.

Meanwhile, Monday's court decision seemed to give Republicans motivation added zest to repeal the bill in Congress.

"That ruling in Florida is a second stake in the heart of the healthcare law," Sen. John Barrasso, MD (R-Wyo.) said on the Senate floor Tuesday.

Sen. Orrin Hatch (R-Utah), vowed the ACA would be repealed.

"I look forward to the day when Obamacare is finally repealed. It may not be next month, it may not be next year, but it will be repealed," said Hatch, who is an attorney. He added that when it is repealed "it will be a triumph for our Constitution."

A repeal vote may come sooner than Hatch expected. The Senate on Tuesday was considering procedural measures that would allow for the Senate to vote on ACA repeal legislation introduced by Sen. Mitch McConnell (R-Kent.) that day as part of an aviation bill.

The other side of the aisle, however, spent the day defending the law.

"The notion that we would repeal the law and walk away from the basic provisions in it is not acceptable to the majority of the American public," said Sen. Dick Durbin (D-Ill.), who is also an attorney. "We are not going to repeal this law."

"What we've passed is entirely constitutional," he said.

This article was developed in collaboration with ABC News.

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