Many have heard about the historic gun rights case going to the Supreme Court. Fewer have heard that this is also a major case for businesses and family values. It could lead to anything from court-ordered Obamacare to same-sex marriage. This is the biggest case of the year, and everyone has a stake in it.

On March 2, the Supreme Court will hear arguments in McDonald v. City of Chicago. It is a gun rights case, challenging Chicago’s categorical ban on handguns. The ban is essentially identical to the D.C. gun ban that was struck down by the Supreme Court in the 2008 case D.C. v. Heller, in which the court held that an absolute ban in the federal city violates the Second Amendment.

The question in this case is whether the Second Amendment applies to cities and states as it does to the federal government. The Bill of Rights applies only against actions of the federal government. Most of the Bill of Rights has since been applied to the states (or “incorporated,” to use the legal term) by the Fourteenth Amendment. The question in McDonald is whether the right to keep and bear arms is incorporated against the states.

So far, so good. More than 70 percent of Americans think the Constitution gives them a right to own a gun, and more than that think any provision in the Bill of Rights should give Americans rights against cities and states, not just the federal government.

The problem is that this case is more about the Fourteenth Amendment than the Second Amendment. Every provision from the Bill of Rights that has been incorporated to the states thus far has been incorporated through the Fourteenth Amendment Due Process Clause. There are all sorts of reasons that Due Process incorporation is problematic, but it’s the way the court has always done it. That’s why the National Rifle Association is focusing on this conventional approach in its brief to the court in McDonald v. Chicago.

However, the team representing Otis McDonald is pushing the court to consider a new route and incorporate the right through another provision, called the Privileges or Immunities Clause. Although that may sound like legal mumbo-jumbo, the reality is that it could change forever our system of federal and state government.

The Privileges or Immunities Clause says states cannot enforce any law that abridges the rights of U.S. citizenship. In 1873, just five years after the Fourteenth Amendment was adopted, the Supreme Court held in a landmark case called the Slaughterhouse Cases that this clause only extends to the states the rights of federal citizenship and strongly suggested that such rights must be found in the Constitution’s text. The high court thus rejected a claim brought by some Louisiana butchers asking it to strike down a state law regulating the slaughtering of animals around New Orleans.

What’s so important about that ruling is that there’s nothing in the Constitution about such an economic right. Had the court accepted the butchers’ argument and struck down the Louisiana law, federal courts would have the power to declare anything they want to be a right of U.S. citizenship and strike down any state or local law they don’t like.

The libertarian lawyers representing Otis McDonald in the current lawsuit acknowledge that their goal is to persuade the court to overrule the Slaughterhouse Cases. Then federal judges could use the Privileges or Immunities Clause to challenge state and local labor laws, commercial laws, employment laws and business regulations across the country.

That would destroy federalism as we know it in this country; life-appointed federal judges could override the decisions made by elected leaders that we, the voters, choose. The people ultimately making those decisions would no longer answer to us.

But that’s not the worst of it.

If the court overrules the Slaughterhouse Cases, the Privileges or Immunities Clause can mean anything courts say it means. The Supreme Court could declare a constitutional right to government-provided health care or “decent” housing, a free college education, a “living wage” or a clean environment, resulting in a court-ordered cap-and-trade system.

It also could completely change American culture, with the court having a new basis upon which to declare constitutional rights to abortion, same-sex marriage, obscene material or a child’s “right” to a public-school education over his parents’ objections. It’s because of these social issues, in particular, that the Family Research Council has weighed in on this case.

Although it should be about the Second Amendment, this gun rights case is, instead, a Trojan horse for everything except guns. It could remake America’s economy and culture. That’s why several conservative groups have weighed in with a brief asking the court to incorporate the Second Amendment through the Privileges or Immunities Clause but to do so without overruling the Slaughterhouse Cases.

McDonald v. Chicago is as big as it gets. All eyes will be on the Supreme Court early next year.

Ken Klukowski is a fellow and senior legal analyst with the American Civil Rights Union and authored the brief mentioned above in the case McDonald v. Chicago. Ken Blackwell is a senior fellow with the Family Research Council and the American Civil Rights Union and is the former U.S. ambassador to the U.N. Human Rights Commission.