The Supreme Court's decision Wednesday to hear a 2nd Amendment challenge to Chicago's handgun ban could open the door to similar lawsuits in cities and states across the nation.

At issue is whether the right to keep and bear arms is a full-fledged constitutional privilege that can be invoked by individuals against the government at all levels, or a freedom that applies only as it concerns the federal government.

Last year, the justices in a 5-4 ruling said for the first time that the 2nd Amendment protected an individual's right to have a handgun at home for self-defense. Though that ruling struck down a handgun ban in the nation's capital -- which is a federal enclave -- it did not decide whether the right extended to states and cities.

After the Civil War, the Supreme Court on several occasions ruled that the 2nd Amendment applied only to national laws. In the last year, gun rights advocates in Chicago and New York went to court to challenge local or state gun restrictions but lost. Judges said they were bound by the high court's 19th century rulings.

On Wednesday, the justices said they would decide the issue in the fall term, which begins Monday.

Legal experts have said that gun rights advocates are likely to prevail in the Chicago case. The five justices who ruled against the District of Columbia handgun ban, led by Antonin Scalia, are likely to extend the same gun rights to states and municipalities.

But lawyers disagree on the practical effects of such a ruling.

Chicago and the nearby village of Oak Park, Ill., are thought to be the only municipalities that enforce a ban on the private possession of handguns. Several other cities, including New York, make it difficult to legally register a handgun. But many other communities have regulations that could be challenged.

Alan Gura, a Virginia lawyer who won last year's ruling and now represents the gun owners in the Chicago case, said Americans had the right to carry guns in public for self-defense, including across state lines.

"This case will not be the end of all gun control, but it means politicians must be aware this is a fundamental right," he said in an interview.

Under the 1st Amendment, restrictions on free speech are suspect and need a strong justification, he said, adding that "the same should be true with gun restrictions."

Gura sued on behalf of four Chicagoans, including Otis McDonald, a retired maintenance engineer who said he had been threatened by drug dealers in his neighborhood.

"I only want a handgun in my house for my protection," McDonald said when the suit was filed. "This lawsuit, I hope, will allow me to bring my handgun into the city legally."

Even if McDonald and the others succeed in striking down the city's ban, a lawyer for the Brady Center to Prevent Gun Violence predicted the ruling would not result in the overturning of most other gun control measures. "It will likely lead to more challenges to state and local gun laws. But when the dust settles, the vast majority of the existing state and local laws will survive," lawyer Dennis Henigan said.

In last year's decision, Scalia agreed that laws restricting felons or the mentally ill from having guns were constitutional. He also agreed the government could keep guns out of airports or government buildings.

The gun rights cause is not limited to conservatives. Libertarians and some self-proclaimed progressives say the court should rule that the Bill of Rights' protections are a privilege of U.S citizenship.

The 14th Amendment says that states may not "abridge the privileges" of a U.S. citizen. At the time the amendment was written, this was seen as extending the rights -- such as freedom of speech or freedom from unreasonable searches -- to protect citizens against state and local officials. However, the Supreme Court disagreed in 1873, and this provision was left unenforceable.

In the Chicago case, the justices agreed to rule on whether the 2nd Amendment and its right "to keep and bear arms" was a privilege of citizenship.

"The correct answer to this question should be important to all Americans, not just those focused on gun rights," said Doug Kendall, president of the Constitutional Accountability Center, a liberal think tank. He and other scholars argue that reviving the privileges clause would strengthen other constitutional rights.

Lawyers for the city of Chicago, however, have urged the justices to turn away the challenge. They said easily concealed handguns posed a special danger in cities.

"Homicides are most often committed with guns, especially handguns," they said, citing a Justice Department report. They also stressed it was legal for homeowners to have a rifle or shotgun for self-defense.

The court said it would hear arguments in the case, McDonald vs. Chicago, in February.