A demonstrator in favor of the Affordable Care Act walks with a sign in front of the Supreme Court in Washington March 4, 2015. (Gary Cameron/Reuters)

With Supreme Court justices divided over the latest challenge to the Affordable Care Act, the legal battle spilled onto the courthouse steps on Wednesday, with attorneys on both sides claiming victory and continuing their arguments before television microphones and flashing cameras.

Though both sides said they thought the arguments before the court had gone well, lawyers supporting the Obama administration seemed a bit more confident that the justices will ultimately uphold the controversial federal tax subsidies for health care at the heart of Wednesday’s oral arguments.

“It was an extraordinary day for the government,” said Neal Katyal, a former acting solicitor general during the Obama administration who is now representing two medical associations that filed briefs on behalf of the government. Katyal hailed what he called current Solicitor General Donald B. Verrilli Jr.’s “magnificent performance,” saying that while it can be difficult to predict how the high court will rule, the questions from the justices “heavily indicated that the court is likely to rule in favor of the government.”

[Highlights from oral arguments]

Elizabeth B. Wydra, who is representing members of Congress who support the law known as Obamacare, told reporters during a driving rainstorm that she is “very confident in the result” of the case. She derided the argument of plaintiffs — that the subsidies should only be available in the 16 states and the District of Columbia that have set up their own insurance marketplaces — as a “gotcha litigation strategy.’’

The lawyers who actually made the arguments on Wednesday, from the Justice Department, declined to comment, though White House spokesman Josh Earnest said the administration was “quite pleased” with Verrilli’s performance.

When his turn at the microphone came, Washington lawyer Michael A. Carvin, who argued for the plaintiffs, said he is “hopeful and confident that the court will recognize the merits of our statutory interpretation and not let the IRS rewrite the plain language” of the Affordable Care Act. He was referring to the Internal Revenue Service regulations that interpreted the law’s language in favor of the Obama administration.

Carvin, who was grilled by the court’s four liberal justices, said he is “gratified that the court had a full and candid exchange of viewpoints.… I have to accept the court’s [earlier] decision that the Affordable Care Act is the law of the land. Now that it’s the law of the land, we need it to be neutrally and fairly interpreted, and that’s exactly why we’re here.”

Carvin added that he did not accept the Obama administration’s contention that slashing the availability of the subsidies would essentially gut the health-care law. Health-care experts have estimated that as many as 7.5 million people in 34 states could lose their subsidies if the challengers prevail.

“Oh no, not at all,” he said. “It seems the leaders in Congress are well prepared to deal with any transition issues. And, I assume the states, if they don’t, will have every incentive to go ahead and create the health-care exchanges they would have created but for the IRS contravention of the law.”

Sam Kazman, general counsel of the Competitive Enterprise Institute — the libertarian think tank that funded the legal challenge — called the IRS’s rule-making “not an inadvertent error but a deliberate disregard of what Congress enacted.’’

“It is our hope that the IRS rule will be invalidated by the court,’’ he said.