Could a city still ban handguns? The justices said the District of Columbia could not, but only because it is a special federal district. The question of the constitutionality of existing city and state gun laws was left unanswered.

That left a large vacuum for the lower courts to fill. Supporters of gun rights filed a flurry of lawsuits to strike down local gun restrictions, and now federal appeals courts have begun weighing in on this divisive issue, using very different reasoning.

One court this month upheld Chicago’s ban on automatic weapons and concealed handguns, while in April a California court disagreed on the constitutional issue.

The differing opinions mean that the whole issue of city and state gun laws will probably head back to the Supreme Court for clarification, leading many legal experts to predict a further expansion of gun rights.

The new cases are fallout from last year’s Supreme Court case, District of Columbia v. Heller, which struck down parts of Washington’s gun control ordinance, the strictest in the country, and stated for the first time that the Second Amendment gives individuals a right to keep and bear arms for personal use. But the court declined to say whether the Second Amendment in general applies to state and local governments.

In January, the United States Court of Appeals for the Second Circuit, in New York, in a ruling joined by Judge Sonia Sotomayor, declined to apply the Second Amendment to a New York law that banned the martial arts device known as chukka sticks. The ban was allowed to stay in place.

Then in April, a three-judge panel of the Ninth Circuit, in San Francisco, ruled that the Second Amendment did apply to the states, even though it allowed a California county to ban guns on government property like state fairgrounds. That case, Nordyke v. King, is being considered for a rehearing by the full Ninth Circuit.

Those two conflicting cases set the stage for two other cases that were heard as one in the Seventh Circuit in Chicago, testing that city’s handgun ban. On June 2, a three-judge panel of the court, led by Chief Judge Frank H. Easterbrook, a well-known conservative, ruled that there was no basis for the court to apply the Second Amendment to the states. Such a decision, Judge Easterbrook wrote, should be made only by the Supreme Court, not at the appellate level.

The right of states to make their own decisions on such matters, Judge Easterbrook wrote, “is an older and more deeply rooted tradition than is a right to carry any particular kind of weapon.”

The lawyers for the plaintiffs, including the National Rifle Association, have asked the Supreme Court to take up the Chicago cases.

A split among the federal appeals circuits, especially on constitutional issues, invites Supreme Court action, said Adam Winkler, a law professor at the University of California, Los Angeles.

“Californians, Hawaiians and Oregonians have a Second Amendment right to bear arms, but New Yorkers, Illinoisans, and Wisconsinites don’t,” Professor Winkler said. “The Supreme Court will want to correct this sooner rather than later.”

The process of applying amendments of the Bill of Rights to the states, known as incorporation, began after the Civil War but had its heyday in the activist Supreme Court of the Earl Warren era. Much of the Bill of Rights, including the First Amendment’s freedom of speech and some rights of criminal defendants, have been applied to the states, but other elements have not, including the Seventh Amendment right to a civil jury trial and the Second Amendment.

Incorporation fell out of favor after the 1960s, but a new generation of largely liberal scholars of law and history have brought it back into the intellectual mainstream, said Akhil Reed Amar, a law professor at Yale University, who supports the process.

“The precedents are now supportive of incorporation of nearly every provision of the Bill of Rights,” Professor Amar said. “Now what’s odd is that the Second Amendment doesn’t apply to the states.”

Sanford Levinson, a law professor at the University of Texas, said he would be surprised if the Supreme Court accepted these gun cases, because some of the conservative justices on the court had scoffed at incorporation arguments in the past and might not want to set a precedent.

Professor Amar, however, argued that the justices would not only take up the case but would also ultimately vote for incorporation of the Second Amendment.

Even if the Second Amendment becomes the controlling law of every state and town, constitutional scholars say it is still unlikely that gun laws would be overturned wholesale. The Supreme Court’s Heller decision last year, notes Nelson Lund, a law professor at George Mason University, “clearly indicates that governments will still have wide latitude to regulate firearms.”

Even the Ninth Circuit in California, while applying the Second Amendment to the states, still upheld the gun ordinance that gave rise to the lawsuit.