United States nationality confers the right to acquire a U.S. passport. The one shown above is a post-2007 issued passport. A passport is commonly used as an identity document and as proof of citizenship.
Citizenship of the United States is a status that entails specific rights, duties and benefits. Citizenship is understood as a "right to have rights" since it serves as a foundation of fundamental rights derived from and protected by the Constitution and laws of the United States, such as the rights to freedom of expression, vote, due process, live and work in the United States, and to receive federal assistance. The implementation of citizenship requires attitudes including allegiance to the republic, participation, and an impulse to promote communities. Certain rights are so fundamental that they are guaranteed to all persons, not just citizens. These include those rights guaranteed by the first 8 Amendments that pertain to individuals. However, not all U.S. citizens, such as those living in Puerto Rico, have the right to vote in federal elections.
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.
— 14th Amendment
National citizenship signifies membership in the country as a whole; state citizenship, in contrast, signifies a relation between a person and a particular state and has application generally limited to domestic matters. State citizenship may affect (1) tax decisions and (2) eligibility for some state-provided benefits such as higher education and (3) eligibility for state political posts such as U.S. senator.
In Article One of the Constitution, the power to establish a "uniform rule of naturalization" is granted explicitly to Congress.
U.S. law permits multiple citizenship. Citizens of other countries who are naturalized as U.S. citizens may retain their previous citizenship, though they must renounce allegiance to the other country. A U.S. citizen retains U.S. citizenship when becoming the citizen of another country, should that country's laws allow it. U.S. citizenship can be renounced by Americans who also hold another citizenship via a formal procedure at a U.S. embassy.
The U.S. military has been an all-volunteer force since the end of the Vietnam War, but male U.S. citizens and non-citizens are still required to register for the military draft within 30 days of their 18th birthday.
Freedom to reside and work. United States citizens have the inalienable right to reside and work in the United States. Certain non-citizens, such as lawful permanent residents, have similar rights; however, non-citizens, unlike citizens, may have the right taken away. For example, they may be deported if convicted of a serious crime.
Freedom to enter and leave the United States. United States citizens have the right to enter and leave the United States freely. Certain non-citizens, such as permanent residents, have similar rights. Unlike permanent residents, U.S. citizens do not have an obligation to maintain residence in the U.S. – they can leave for any length of time and return freely at any time.
Voting for federal office in all fifty states and the District of Columbia is restricted to citizens only. States are not required to extend the franchise to all citizens: for example, several states bar citizen felons from voting, even after they have completed any custodial sentence. The United States Constitution bars states from restricting citizens from voting on grounds of race, color, previous condition of servitude, sex, failure to pay any tax, or age (for citizens who are at least eighteen years old). Historically, many states and local jurisdictions have allowed non-citizens to vote; however, today this is limited to local elections in very few places. Citizens are not compelled to vote.
Right to apply for federal employment. Many federal government jobs require applicants to have U.S. citizenship. U.S. citizens can apply for federal employment within a government agency or department.
Citizens are required to file U.S. taxes even if they do not live in the U.S.
Jury duty is only imposed upon citizens. Jury duty may be considered the "sole differential obligation" between non-citizens and citizens; the federal and state courts "uniformly exclude non-citizens from jury pools today, and with the exception of a few states in the past, this has always been the case".
Taxes. In the United States today, everyone except those whose income is derived from tax-exempt revenue (Subchapter N, Section 861 of the U.S. Tax Code) is required to file a federal income tax return. American citizens are subject to federal income tax on worldwide income regardless of their country of residence.
Census. A response to the decennial census is mandated by Article I, Section 2 of the United States Constitution and by Title 13 of the United States Code of all residents.
Consular protection outside the United States. While traveling abroad, if a person is arrested or detained by foreign authorities, the person can request to speak to somebody from the U.S. Embassy or Consulate. Consular officials can provide resources for Americans incarcerated abroad, such as a list of local attorneys who speak English. The U.S. government may even intervene on the person's behalf. Non-citizen U.S. nationals also have this benefit.
Increased ability to sponsor relatives living abroad. Several types of immigrant visas require that the person requesting the visa be directly related to a U.S. citizen. Having U.S. citizenship facilitates the granting of IR and F visas to family members.
Ability to invest in U.S. real property without triggering FIRPTA. Perhaps the only quantifiable economic benefit of U.S. citizenship, citizens are not subject to additional withholding tax on income and capital gains derived from U.S. real estate under the Foreign Investment in Real Property Tax Act (FIRPTA).
Transmission of U.S. citizenship to children born abroad. Generally, children born to two U.S. citizen parents abroad are automatically U.S. citizens at birth. When the parents are one U.S. citizen and one non-U.S. citizen, certain conditions about the U.S. citizen's parent's length of time spent in the U.S. need to be met. See United States nationality law for more details. Non-citizen U.S. nationals also have a similar benefit (transmission of non-citizen U.S. nationality to children born abroad).