More than any other nation, America beckons those who seek opportunity and a better future for themselves and their families. Immigration strengthens our social capital, deepens our national patriotism, and expands our general economy. 

Naturalization—the idea of a foreigner becoming an equal citizen as if by nature—follows directly from America's political principles. Individuals have a natural right to emigrate from their homeland, but they may only immigrate to this country with the consent of the American people as expressed through U.S. laws. With that consent, a person of any ethnic heritage or racial background can become, in every sense, an American citizen.

What about those who are born here?

After the Civil War, the 14th Amendment (overturning, in part, Dred Scott v. Sandford, which said that no black could be a U.S. citizen) clarified the conditions of citizenship: "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the States wherein they reside."

Many today assume the second half of the citizenship clause ("subject to the jurisdiction thereof") merely refers to the day-to-day laws to which we are all subject. But the original understanding referred to political allegiance. Being subject to U.S. jurisdiction meant, as then-Chairman of the Senate Judiciary Committee Lyman Trumbull stated, "not owing allegiance to anybody else [but] subject to the complete jurisdiction of the United States." The author of the provision, Sen. Jacob Merritt Howard of Michigan, pointed out that the jurisdiction language "will not, of course, include foreigners."

It was in 1898 (in United States v. Wong Kim Ark) that the Supreme Court expanded the constitutional mandate, holding that the children of legal, permanent residents were automatically citizens. While the decision could be (and is often) read more broadly, the court has never held that the clause confers automatic citizenship on the children of temporary visitors, much less of illegal residents.

The broader reading is a constitutional misreading. Not only does it grant citizenship to the children of illegal immigrants, it also gives full due-process rights to the likes of Taliban fighter Yasir Hamdi (born in the United States of visiting Saudi parents and captured fighting U.S. soldiers 20 years later in Afghanistan).

But it is the principle of the matter that is most problematic. The broad claim of automatic birthright citizenship traces its roots more to the feudal concept of perpetual allegiance of subjects to kings, rather than equal rights and the consent of the governed. It violates bedrock American principles and undermines the rule of law.

What is to be done?

While the Constitution defines the basic conditions, the decision whether and how far to offer citizenship beyond that (i.e., who is subject to the jurisdiction of the United States) is a policy judgment historically left to Congress. It could, for instance, extend birthright citizenship to legal permanent residents (consistent with Wong Kim Ark) but exclude, in the future, the children of illegal or temporary residents.

Nobody is talking about repealing the 14th Amendment, or taking away anyone's citizenship. Nor must we amend the Constitution. But Court needs to clarify the extent of birthright citizenship. It should do so as part of a clear and meaningful policy concerning immigration, naturalization, and citizenship that is consistent with the core principles and highest ideals of the United States.

Matthew Spalding is the director of the B. Kenneth Simon Center for American Studies at the conservative Heritage Foundation.