The U.S. Supreme Court will almost certainly extend the scope of the Second Amendment right to bear arms to limit state and federal regulation of firearms, based on oral arguments in McDonald v. City of Chicago on Tuesday.

But comments from the justices made it clear they want to do it the old-fashioned way — through the 14th Amendment’s due process clause, rather than via the same amendment’s “privileges or immunities” clause, which had been advanced as a better way to bolster a range of rights including economic rights. Several justices also indicated that, as with other individual rights, states and cities will be able to impose some regulations on firearms.

If it takes these steps, the Court will complete the constitutional sea change that began in 2008 when, in D.C. v. Heller, the Court first ruled that the awkwardly worded Second Amendment embodied an individual right to bear arms, rather than a right related to state militias. Because that ruling applied to the District of Columbia, a federal enclave, a sequel was needed to determine if the right also applied to or incorporated states and localities.

The follow-up case came in the form of a challenge, filed within hours of the Heller decision, against long-standing ordinances in Chicago and Oak Park, Ill., which, like the District of Columbia, banned handguns altogether. The U.S. Court of Appeals for the 7th Circuit ruled in favor of the handgun bans because the Heller decision did not yet apply to state or local laws.

In hourlong arguments before a packed courtroom, the justices acted as if the incorporation question had already been answered affirmatively, and they focused instead on which clause of the Constitution should be invoked to reach the result.

Alan Gura of Gura & Possessky in Alexandria, Va., who won the Heller case in 2008, argued in Tuesday’s case on behalf of Chicago residents who wanted handguns for personal safety. But Gura faced a more hostile Court this time, because he was making the untested argument that the 14th Amendment’s guarantee that states may not abridge the “privileges or immunities” of citizenship was the best route to applying the Second Amendment to the states.

Almost immediately, Chief Justice John Roberts Jr. told Gura, “it’s a heavy burden for you to carry,” because using that clause would require the Court to overturn the Slaughterhouse cases of 1873, “which have been the law for 140 years.” Gura said that precedent did not deserve to stand.

Next came Justice Antonin Scalia, who asked whether the privileges or immunities route was “easier” than invoking the traditional due process argument for incorporating the Bill of Rights to the states. When Gura answered no, Scalia exclaimed, “Then if the answer is no, why are you asking us to overrule 150, 140 years of prior law?” Unless, he said, “you are bucking for a place on some law school faculty.” Scalia also said that “What you argue is the darling of the professoriate.”

Gura said wanly, “I have left law school some time ago and this is not an attempt to return.”

Scalia persisted. “Why do you want to undertake that burden instead of just arguing substantive due process, which as much as I think it’s wrong — even I have acquiesced in it?”

Justices Anthony Kennedy and Stephen Breyer seemed concerned about possible unforeseen consequences of adopting the new way of incorporating the Second Amendment. “How are federal judges supposed to carry this out?” Breyer said. “I want to see where we are going.”

Gura finally backed off, acknowledging that “we would be extremely happy if the Court reverses the lower court based on the substantive due process theory that we argued in the 7th Circuit.”

Former Solicitor General Paul Clement, now at King & Spalding, spoke next, representing the National Rifle Association on the same side as Gura. Picking up on the Court’s wariness about privileges or immunities, Clement reassured the justices that “the case for incorporating the Second Amendment through the due process clause is remarkably straightforward.”

Justice John Paul Stevens, who led the dissent in Heller, asked Clement a question that almost presumed that the Second Amendment does apply to state laws: “Why does this incorporation have to be every bit as broad as the Second Amendment itself?” Stevens seemed to be seeking a compromise approach that would apply only part of the Second Amendment to states, but it did not seem to catch on.

By the time James Feldman rose to argue on behalf of Chicago and Oak Park, his position — that the Second Amendment should not apply to states and localities — seemed to fall on deaf ears. Feldman, a Washington solo practitioner and a veteran of the solicitor general’s office, argued that the Second Amendment is different from the Bill of Rights because firearms “are designed to injure and kill.” As a result, states and localities should have more leeway than in other contexts to limit the right, Feldman said. “Our history for the last 220 years has been of reasonable state and local regulation of firearms that responds to local conditions.”

Justice Sonia Sotomayor, in an almost consoling tone, asked Feldman, “Would you be happy if we incorporated [the Second Amendment] and said reasonable regulation is part of the incorporation?” Feldman did not answer directly except to assert that Chicago’s ordinance — which allows ownership of long arms but not handguns — is an example of reasonable regulation.

After the argument, Cato Institute scholar Ilya Shapiro, a supporter of the “privileges or immunities” strategy, lamented its seeming failure before a skeptical Court. “It is a shame that the Supreme Court seems to be wasting a perfect opportunity to bring constitutional law closer to the Constitution,” Shapiro wrote on Cato’s Web site. “It is an even greater shame that it is wasting this chance to use guns to protect liberty.”

Tony Mauro can be contacted at tmauro@alm.com.