“All persons born or naturalized in the United States and subject to the jurisdiction thereof are citizens of the United States.”

Those words, the first sentence of the 14th Amendment, embody a birthright that millions of Americans have enjoyed. At one point during Supreme Court Justice Samuel A. Alito Jr.’s Senate confirmation hearings last month, New York Democrat Charles E. Schumer pressed him on whether he agreed that the sentence was a “fairly clear and straightforward provision of the Constitution.”

“All persons means all persons,” Schumer said encouragingly. “That’s pretty easy.”

It was not easy enough for Alito to answer on the spot, however. “It may turn out to be a very simple question; it may turn out to be a complicated question,” he said. “I would have to go through the whole judicial decision-making process before reaching a conclusion.”

Simple or not, Schumer’s question — whether those words would prevent Congress from passing a law denying citizenship to someone born on U.S. soil — lies at the heart of an intensely emotional debate. For now, it is on the periphery of congressional consideration of illegal immigration, but someday relatively soon the question of birthright citizenship may reach the Supreme Court.

That outcome would suit Republican Rep. Nathan Deal of Georgia just fine. Deal, leader of an effort in Congress to bar the children of illegal immigrants from receiving automatic citizenship, says the language in the 14th Amendment is murky and has been misinterpreted over the years. Furthermore, he says, the words of the amendment have been a magnet for immigrants who enter the country illegally, have “anchor babies,” then claim that deportation would cruelly separate them from their family.

The Supreme Court has never directly addressed the ambiguities in the Constitution that are seen by Deal and others who want to limit the 14th Amendment’s scope. That creates an opening for Congress to restrict birthright citizenship — and then let the courts decide whether that limit is constitutional. In Deal’s view, the phrase “subject to the jurisdiction thereof” is ambiguous enough that it might exclude children of parents who are foreign nationals. Automatic citizenship is now granted to anyone born in the United States, even the children of tourists.

Opponents say Deal and his supporters — his legislation had 83 cosponsors as of last week — are overreaching. All immigrants, legal or not, are subject to the jurisdiction of U.S. laws, says California’s Howard L. Berman, the No. 2 Democrat on the House Judiciary Committee. Furthermore, Berman says he is baffled at conservative Republicans, who normally insist on a textual reading of the Constitution, building a case that the court must “interpret” the 14th Amendment. “The fact that the court has not had reason to explore this is because Congress has not had the inclination to adopt something that is so contrary to the plain meaning of those words,” he said.

Schumer had used much the same argument in framing his questions to Alito. “President Bush has stated his beliefs that judges should be strict constructionists, rigidly adhering to the letter of the Constitution,” he told the judge. But Alito refused to be drawn in. “There are active legal disputes about the meaning of that provision at this time,” he said.

For now, the debate is academic. Republican leaders prevented Deal’s measure from being considered in December as a proposed amendment to an already contentious border security bill, which went on to be passed by the House. But even if he had been successful, his legislation would have to pass an even more skeptical Senate, where leading Republicans call the effort “futile.”

But with public discontent over illegal immigration growing, Deal believes he has a case and a chance. “I think any vehicle that would get the issue before the Supreme Court is the right vehicle,” he said.

Should that day come, Deal and others would look for guidance to John C. Eastman, a constitutional law professor at Chapman University in Orange, Calif., and director of the Center for Constitutional Jurisprudence at the conservative Claremont Institute.

Eastman testified before a House Judiciary subcommittee in September that the Constitution’s citizenship clause has been misinterpreted for more than a century.

Eastman has zeroed in on what the 1866 Civil Rights Act — a statutory forerunner of the 14th Amendment, which was added to the Constitution two years later— said about citizenship. Drafted to guarantee citizenship to recently freed slaves, the law was more direct in who was eligible: “All persons born in the United States, and not subject to any foreign power, excluding Indians not taxed, are hereby declared to be citizens of the United States.” The 14th Amendment employed the more ambiguous clause “subject to the jurisdiction thereof,” instead of “not subject to any foreign power.”

This leaves little doubt in Eastman’s mind that Congress understood a clear distinction between “basic territorial jurisdiction” such as traffic laws, and “complete jurisdiction”, which encompasses a person’s allegiance to a nation.

The Supreme Court confirmed his assessment in Elk v. Wilkins, an 1884 ruling that rejected a citizenship claim by John Elk, an American Indian who was born on a reservation but subsequently moved off, and therefore was denied his right to vote.

But Eastman said the court “misread” the citizenship clause 14 years later in United States v. Wong Kim Ark. Wong Kim Ark was born in the United States to Chinese parents. After a visit to China, he was denied readmission to the United States. An 1882 law denied birthright citizenship to the decedents of Chinese nationals, and the government claimed that those children would be subject to the rule of its emperor. But the court ruled that common law and the 14th Amendment guaranteed citizenship to all persons born in the United States, regardless of their ethnic heritage.

Jack M. Balkin, a constitutional law professor at Yale University, said that even though the original understanding of the amendment may be ambiguous, the Wong Kim decision offered clarity.

“Now the question is ‘what if Congress passes a law that says children of illegal immigrants are not citizens?’ ” he asked. “Wong Kim Art seems to suggest the statute would be unconstitutional. But you could distinguish that it does not specifically involve illegal aliens.”

What the court would do, however, is difficult to predict, Balkin said, particularly since it has two new members and virtually no modern case law about the issue to rely on.

“We should not assume it’s an easy case,” Balkin said. He suspects the court would “tilt” toward striking down Deal’s bill if it became law. However, “it’s not a slam-dunk either way.”

Building a legal argument might not matter if the supporters cannot muster the political will for a vote. And while they might ultimately have the numbers, Deal and company currently lack the muscle to bring the debate to the House floor.

On the House Judiciary panel, Chairman F. James Sensenbrenner Jr., a Wisconsin Republican, and Berman rarely find themselves aligned on issues, yet the two have maintained a cordial, working relationship over the years. Sensenbrenner never told Berman why the Deal measure had been sidetracked, but he made a point to put Berman at ease about the amendment. “He did tell me it would not be offered,” Berman recalled. “He sort of said it with a smile.”

The issue appears to have even less support in the Senate. Deal’s bill has no companion legislation, and even some of those taking the hardest line on illegal immigration would prefer to steer away from a debate on the meaning of citizenship.

“I believe it would be futile because the United States Supreme Court would strike down any limitations on citizenship rights for individuals born in the United States,” said Republican Sen. John Cornyn. He has offered a broad immigration bill that has been well received by interest groups seeking tighter border security and stricter enforcement of immigration laws. But eliminating birthright citizenship is not part of the measure.

Cornyn, a former Texas Supreme Court judge and state attorney general, noted that the Supreme Court offered a hint in 1982, when it wrote in Plyer v. Doe that public schools could not deny the children of illegal immigrants an education. But Cornyn, who is generally a close ally of President Bush, is not simply hedging his bets. He considers the proposal divisive and unnecessary.

“I think it’s important that we come out of this immigration reform not appearing to want to punish people gratuitously,” Cornyn said. “I think that would be viewed as harsh and punitive, and I don’t think it would be a good idea from a policy standpoint or a political standpoint.”

Even some of Deal’s biggest supporters doubt the proposal can succeed. Florida Republican Mark Foley has signed on, but he is also sponsoring a proposed constitutional amendment that would achieve the same purpose.

For eight years Foley has been championing the amendment route, which requires a two-thirds vote in the House, the Senate and the approval of 38 state legislatures.

“My view is the 14th Amendment was rather certain in its application,” said Foley. “Legislatively, I still am not comfortable with Nathan’s solution. I think a court could strike it down.”

Deal says that’s a common reaction from his colleagues, one that tells him he needs to do a better job educating them. But he’s confident the court, if presented with an actual controversy based on his legislation, would be intrigued.

“The crux of the matter is getting a case before the court so they could rule,” he said. “Normally you would only pass constitutional amendments where you were trying to overrule a court ruling. We haven’t had a square ruling on that yet. I think it all really comes down to that.”

Senate immigration bill, p. 442; Deal’s bill is HR 698; Foley’s proposed constitutional amendment is H J Res 41; House passage of the border control bill (HR 4437), 2005 CQ Weekly, p. 3396.