Non-U.S. citizens may be protected under the Constitution under certain amendments. But the issue is not simple enough to be answered by a "yes" or "no." The decision is often made on a case-by-case basis by the Supreme Court, as interpreters of the Constitution.

Definition of a Citizen

The framers of the Constitution did not initially define U.S. citizenship. This lack of definition was used by the Supreme Court in the 1857 Dredd Scott case to deny U.S. born African-Americans citizen rights. In 1868, The 14th Amendment was ratified to rectify that. The 14th Amendment defines citizens as "all persons born or naturalized in the United States and subject to the jurisdiction thereof." The 14th Amendment did not include people born in a foreign country to American parents in its definition. Citizenship in those cases is granted by the Immigration and Nationality Act of 1952.

Citizen-only Rights

A few rights only apply to citizens. The Constitution extends the right to vote to citizens aged 18 and over. Only citizens have the right to run for federal offices. Additionally, only natural-born citizens of the United States may run for president. A naturalized citizen cannot be president even if he meets other qualifications for office.

Persons' Rights

The 14th Amendment says no state may "deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws." The fact that the Constitution does not specifically use the word ''citizens'' in that part of the amendment gives the Supreme Court a basis to conclude that non-citizens are protected.

Subject to Interpretation

In addition to the equal protection granted in the 14th Amendment, the Supreme Court has held that non-citizens are entitled to due process under the Fifth Amendment. They have the right to hold non-government jobs and send their children to public school. In contrast, the Supreme Court has denied non-citizens the right to have state-funded vocations such as teachers or police officers. The Court has also held that foreign nationals could be detained or deported based on nationality, such as in the case of the USA Patriot Act of 2001.