The controversial birth control mandate under Obamacare is likely going to the Supreme Court for a final verdict, in what would be a landmark case with potentially far-reaching implications. Appeals courts have issued split decisions on the constitutionality of requiring employer-provided insurance plans to cover contraception for female employees without co-pays.

Progressive legal advocates view it as potentially a sequel to the notorious 2010 Citizens United ruling in that it could dramatically expand the concept of corporate personhood.

“It doesn’t make sense to view a corporation as a person trying to exercise religion,” said Elizabeth Wydra, chief counsel for the liberal-leaning Constitutional Accountability Center. “To say that a corporation can engage in religion — something that was considered at the founding to be a fundamental right of conscience — would be taking the corporate personhood element of Citizens United to an absurd result.”

CAC wrote a 16-page brief — titled “Can Corporations Pray?” — arguing that the Supreme Court should not extend personhood benefits to for-profit businesses. “The Free Exercise Clause is perhaps the quintessential example of a purely personal constitutional guarantee that does not extend to business corporations,” the brief reads. “Business corporations cannot pray, express devotion to a god, and do not have a religious conscience.”

The Supreme Court tends to have the final word when appellate courts are split on the validity of a federal law. There are several cases percolating on this issue but experts believe the one most likely to be taken up involves Hobby Lobby, a for-profit Oklahoma-based retail chain with devout Christian owners. It is the only one of three suing groups that won on the appellate level, at the 10th Circuit. The case also deals with the issues in the most comprehensive way and is seen as the best vehicle to resolve the underlying disputes. The mandate’s opponents and proponents have called on the Court to hear it. The expectation is it’ll announce in November, hear oral arguments next spring and render a decision by the end of June 2014.

Many types of contraceptives were placed among a package of essential preventive services, as certified by the Institutes of Medicine, that the law requires non-church health plans to cover without co-pays, on the basis that broadening access to these services makes people healthier and saves money. Opponents are driven both by an urge to dismantle the Affordable Care Act and by a desire to expand religious liberty to the extend possible.

The First Amendment isn’t the main issue because the Court said in a 1990 decision that religious individuals and institutions exemptions may not be exempted from generally applicable laws. (Ironically, the majority opinion was written by Justice Antonin Scalia.) The bigger question is whether the mandate violates a law Congress passed in 1993 to limit the reach of that ruling, called the Religious Freedom Restoration Act. It requires that laws burdening the free exercise of religion be narrowly tailored to meet a compelling governmental interest.

“Hobby Lobby filed suit in an effort to defend its constitutional freedom to carry out its mission in a way consistent with its owners’ religious principles,” said the Becket Fund For Religious Liberty, a conservative law firm supporting Hobby Lobby.

The current makeup of the Supreme Court — the most conservative since the 1930s, according to one study — gives progressives plenty of room for concern and social conservatives plenty of room for hope. Much like the case about the constitutionality of the Affordable Care Act itself, many legal experts initially didn’t expect the contraception lawsuits to make it very far. Now proponents of the rule have a real fight on their hands.