The Supreme Court’s 2008 ruling in D.C. v. Heller was a constitutional earthquake, breathing life into the Second Amendment as a guarantee of an individual right to bear arms.

But the aftershock of that decision is beginning to transform the constitutional landscape well beyond gun rights, in ways that have liberals cheering and even joining hands with one-time adversaries like the National Rifle Association.

In a follow-on case pending before the 7th U.S. Circuit Court of Appeals, a progressive legal group and liberal law professors including Yale Law School’s Jack Balkin earlier this month joined gun-rights advocates in urging that the right established in Heller, which involved only the District of Columbia, be extended to apply against gun restrictions in the 50 states. The case isMcDonald v. Chicago, a challenge to that city’s strict gun control law and, no matter what, the outcome is likely to be appealed to the Supreme Court.

But these academics and the liberal Constitutional Accountability Center, which filed a brief in the case, have not suddenly taken up the Second Amendment cause, Charlton Heston-style. Rather, they joined the case to urge the court to adopt a new way of making the rights protected by the federal Constitution apply to the states (a process known as “incorporation”).

That new pathway runs through the long-dormant “privileges or immunities” clause of the 14th Amendment. In the view of scholars and historians of all political stripes, the clause provides the strongest legal foundation for applying the Bill of Rights to the states. The language — “No state shall make or enforce any law which shall abridge the privileges and immunities of citizens of the United States” — is broad and clear, advocates say, and could be used to incorporate the entire Bill of Rights to the states, wholesale. It would replace the narrower and more piecemeal way in which the Bill of Rights was usually made binding on the states, right by right, during the 20th century — namely, the 14th Amendment’s due process clause.

Use of the due process clause has led to “the constitutional equivalent of a food fight” with conservative justices increasingly wary of expanding or creating new rights because of the clause’s process-oriented scope, says Douglas Kendall, founder of the D.C.-based Constitutional Accountability Center. Kendall says invoking “privileges or immunities” would have a “lift-all-boats” effect, strengthening free speech, and possibly even abortion and gay rights, at the same time that it bolsters the right to bear arms.

Kendall had few qualms about joining McDonald on the side of gun-rights advocates. “The conversation on this clause has begun, and there are very important progressive values at stake in the outcome,” Kendall says. “We need to be in that conversation.”

‘MORE THE MERRIER’

At a conference in D.C. in January co-sponsored by the American Constitution Society and other civil rights groups, John Payton, president of the NAACP Legal Defense and Educational Fund, endorsed Kendall’s campaign. Pointing to long-cherished individual rights, Payton said, “If you read the history, these rights were supposed to come in as privileges or immunities of being a citizen of the United States.”

So, why does the “privileges or immunities” clause need reviving? Because it was gutted by the Supreme Court in the notorious 1873 Slaughterhouse Cases,which upheld a state-endorsed slaughterhouse monopoly. The Court ruled that the federal immunities clause, which had been invoked to challenge the monopoly, only applies to federal citizenship, not state citizenship. That is a distinction with little meaning today, but at the time had the effect of turning the clause into a dead letter. Dissenting Justice Noah Swayne said the majority in Slaughterhouse had transformed “what was meant for bread into a stone.” The ruling led succeeding justices to turn to the due process clause as the way to bind states to federally declared rights.

But in recent decades, new scholarship on the 14th Amendment has shown that its authors intended the privileges clause to be a broad, robust way of applying constitutional rights to the states — especially for freed slaves, and especially, it seems, for the right to bear arms.

The high court showed a glimmer of interest in reviving the clause in 1999, when in Saenz v. Roe it struck down a California law that gave lesser welfare benefits to new residents. Justice John Paul Stevens invoked the clause, and though Justice Clarence Thomas dissented, he said in a footnote that he was open to “re-evaluating its meaning.”

In Heller itself, Justice Antonin Scalia in a footnote said the Court was not addressing the incorporation issue, but noted that a key precedent “did not engage in the sort of Fourteenth Amendment inquiry required by later cases.” That could be a hint that it’s time for a new inquiry.

Gun-rights advocates respond with a “more the merrier” attitude when asked if liberals are hijacking the Chicago gun case for their own purposes.

Alan Gura of Gura & Possessky in D.C. and Virginia, who won the Heller caseand filed the McDonald appeal in Chicago, said the participation of liberal groups and scholars did not surprise him. “There are wider consequences than the Second Amendment” in his appeal, he acknowledges.

Adds Stephen Halbrook, a Fairfax, Va., practitioner who is part of the NRA’s team in a companion case to McDonald, “It’s an exciting case, and we’re pleased with all the company we can get.” He notes that the NRA’s brief argues for incorporation of the Second Amendment the old-fashioned way, through the due process clause, not the privileges clause.

On the other side, Dennis Henigan, legal director of the Brady Campaign to Prevent Gun Violence, says of the liberals’ brief, “It’s unfortunate that they would choose to participate in a gun case to grind that particular ax” because of the public safety implications. That said, Henigan added that applying the Second Amendment right to the states may not have major impact, so long as it is the restricted right announced in Heller.

BEYOND ‘HELLER’

Beyond the Second Amendment, one possible result of a strengthened privileges or immunities clause could be a change in the criminal justice system for some states. The Fifth Amendment’s requirement of indictment by grand jury in major crimes has never been made binding on states, half of which don’t currently require grand juries to bring indictments. That could change.

The libertarian Institute for Justice also says that a stronger foundation for individual rights could benefit business or contract rights, too. The institute filed its own brief in McDonald, asserting that the 14th Amendment was passed to give freed slaves economic as well as personal liberty. “In some states, it was illegal for a black man to leave his employer’s property without permission; in others, blacks could be flogged for breaking a contract,” says Chip Mellor, the institute’s president.

Should the fact that conservatives like Thomas and Scalia are interested in reviving the clause give liberals pause? In the process of strengthening some rights through the privileges and immunities clause, could the Court weaken others?

Kendall does not see much downside to fortifying basic rights. And he has not gotten pushback from liberal colleagues about joining the gun case or jumping into the debate over the clause at the same time as conservatives. “It’s remarkable how broad a consensus there is that privileges and immunities is the right way to go.”