(Bloomberg Business) -- The Supreme Court briefs are in, and wecan now say that big business backs Obamacare.

The justices will hear oral arguments March 4 in the latest case challenging thePatient Protection and Affordable Care Act. At issue is theact’s provision of federal tax subsidies to make health insuranceaffordable for the less-well-off. The plaintiffs are fourVirginia residents who say they can’t afford coverage but claimthey want to be ineligible for subsidies. If that seems like an oddposition, well, ordinarily it would be. The stance becomes moreunderstandable, though, when one peeks beneath the legal papers andsees that the plaintiffs are backed by a range of conservativeand libertarian interest groups whose real goal is to cripple, ifnot kill, PPACA.

We’ll return to the larger agenda behind the challenge. Butfirst, a quick observation about interest groups that aren’t urgingthe destruction of PPACA.

Large corporate lobbying outfits, such as the U.S. Chamber of Commerce, often file“friend of the court,” or amicus, briefs in Supreme Court casesaffecting business and the economy. This time, they haven’t.The reason can be inferred from the amicus briefs ofmore narrowly focused insurance and health care interests thathave filed to support the White House. With a significant portionof its constituency urging the justices to leave PPACA in place,the Chamber couldn’t very well join the attack. (In responseto my inquiry, the Chamber promised to comment on its non-filingbut hadn’t done so as of publication).

Among those filing amicus briefs defending health reform areHCA, the American Hospital Association, America’s Health Insurance Plans, the NationalAlliance of State Health Co-ops, the Catholic Health Association ofthe United States, the American Cancer Society, and the NationalAssociation of Community Health Centers. The insurance and medicalindustries share the administration’s goal of seeing millions morepeople covered because that translates into millions more customersseeking the services of carriers, hospitals, and doctors.

Beyond additional customers, health care businesses arguethey also care about consumer welfare.

“We will not mince words,” the American Hospital Associationdeclares in its brief. The plaintiffs’ position, “if accepted,would be a disaster for millions of lower- and middle-incomeAmericans. [PPACA’s] subsidies have made it possible for more than9 million men, women, and children to have health coverage—some forthe first time in years; some, no doubt, for the first time intheir lives. That coverage allows them to go to the doctor whenthey are sick, and to do so without fear that the resulting billcould leave them in financial distress.”

On the other side, the challenge to PPACA is a production of theCompetitive Enterprise Institute, awell-known anti-regulatory advocacy group. Procedural questionshave arisen over whether the four plaintiffs recruited by theCEI are appropriate choices. Leaving those issues to one side, themotives of the challengers can easily be discerned from the briefsbacking the plaintiffs. They include the conservative advocacygroups Judicial Watch, American Center for Law and Justice,Mountain States Legal Foundation, Pacific Research Institute, CatoInstitute, Washington Legal Foundation, Missouri Liberty Project,and Landmark Legal Foundation.

PPACA opponents focus less on the practical consequences ofsweeping aside health reform and more on principles ofgovernment.

“Executive lawmaking—which has alas become commonplace—poses asevere threat to the separation-of-powers principles that undergirdthe Constitution and ultimately the rule of law itself,” argues thelibertarian Cato Institute in its amicus brief. “Accordingly, thisCourt should vacate the IRS rule that provides subsidies in statesthat did not establish exchanges. This rule violates Congress’slimitation of such subsidies to insurance bought through exchanges‘established by the state.’”

The last two sentences take us to the statutory intricacies ofthe case. In the first Supreme Court challenge to PPACA three yearsago, justices voted 5-4 that Congress possessed constitutionalauthority to require that people buy health insurance. Thistime around, the assault concerns the subsidies meant to make thatmandated coverage affordable.

PPACA has three pillars: banning insurers from denying coveragebased on preexisting conditions; mandating that everyone buyinsurance to ensure healthy people participate; and subsidizingless-well-off consumers. The current Supreme Court caseaddresses who can get those critical tax subsidies, without whichthe mandate would collapse, probably causing the entire program tounravel.

Read literally, the law provides subsidies for policiespurchased via an “exchange established by the state.” The problemwith that language is that only 16 states and the District ofColombia have set up their own exchanges. Most Republicanpoliticians refused to go along with PPACA, meaning that residentsof 34 states have to seek insurance on exchanges set up by thefederal government.

Charged with interpreting PPACA, the Internal Revenue Serviceconcluded Congress couldn’t have intended to gum up the statutorymachinery with this state-versus-federal distinction. The IRSestablished a rule that everyone, regardless of their stateresidency, was eligible for the subsidies. The justices will ruleon the reasonableness of that interpretation. In the normal courseof judicial business, courts defer to agency readings of ambiguousstatutory verbiage. The challengers insist there’s nothingambiguous about the words “exchange established by the state.”

Business interests, or at least health-related businessinterests, are siding with the IRS. Now it’s up to thejustices.

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