Republicans grew more confident than ever today that the Supreme Court will strike the entire 2010 health care reform law after several justices expressed concerns about whether they could merely carve out the individual mandate at its heart.

Meanwhile, Democrats again clung nervously to the hope that three days of tough questions don’t necessarily mean the law is going down.

Sen. Kelly Ayotte (R-N.H.), who attended today’s session, noted that she’s from the “Live Free or Die” state. She said she was heartened by the justices, led by Antonin Scalia, doubting whether the bill could or should be salvaged.

“Justice Scalia had it right,” she said, when he argued that if the heart of a bill is unconstitutional, the rest should go.

“I don’t think it’s the court’s role to see which of these provisions would have passed on its own,” she said.

She pointed to Scalia’s contention that the so-called “Cornhusker kickback” included to secure Sen. Ben Nelson’s (D-Neb.) vote as just one example of a questionable side provision.

Ayotte, who has argued a severability issue before the court, also noted that Congress did not include a severability clause protecting the rest of the act.

“They did this on purpose,” she said.

Sen. Mike Lee (R-Utah), who has also been sitting in on the proceedings, pointed to the arguments about whether the law’s expansion of Medicaid is constitutional, calling the administration’s argument a “stunning example of federal overreach.”

Lee said he’s heard a lot of support on the court for protecting states from coercion and limiting the government’s powers after more than 80 years of expanding the federal government.

Sen. Kay Bailey Hutchison (R-Texas) also said it appeared to her that several justices were leaning toward striking down the whole law, including Justice Anthony Kennedy, who is widely seen as the swing vote.

In his questioning, Kennedy expressed concern that taking out the mandate but letting the rest of the law stand could be a more extreme use of judicial power than striking the law in its entirety. That’s because many economists believe the law’s requirement that insurance companies cover pre-existing conditions, among other things, would send insurance rates skyrocketing without a larger pool of insured Americans.

Democrats still hoped the justices will ultimately support the law and are merely exploring all of the issues.

“I am glad, as I think any of us who practice law are, to see the intense questions from the justices,” Sen. John Kerry (D-Mass.) said. “They’re engaged and thoughtfully working through these issues. But questions are a legitimate way of probing the basis of their own thinking. They are not an indication of a judgment made or a vote ready to be cast.”

Kerry, noting he worked on the law as a senior member of the Finance Committee, said that during the drafting, “we worked with some of the brightest and thoughtful and experienced Constitutional lawyers in order to make sure that the law was constitutional.”

He said he’s confident “they will decide they don’t want to go back to a nation where you get cancer and you get a letter from your insurance company telling you you’re no longer covered.”

Sen. Richard Blumenthal (D-Conn.), meanwhile, appeared to set the stage to attack the court’s decision if they vote the law down.

Blumenthal noted that the court has to presume the law is constitutional.

To overturn the law, “the court would have to stretch, it would have to abandon and completely overrule a lot of modern precedent, which would do grave damage to this court in credibility and power,” he said. “The court commands no army, it has no money, it depends for its power on its credibility and its reputation. Ultimately, people obey it because it has that credibility, and the court risks grave damage if it strikes down a statute of this magnitude and importance.”

He said that, as someone who has argued cases before the court, at least three justices haven’t made up their mind: “I think all of the predictions are worth what you’re paying for them, they mean nothing at this point.”