An Oath of Allegiance is a verbal promise in which an individual swears allegiance and loyalty to a particular country, state, monarchy, political institution, individual or group of individuals. In the United States, naturalized citizens, military personnel, and citizens assuming public offices such as presidents and judges, swear their allegiance to the United States Constitution. An Oath of Allegiance in other countries also commonly involves swearing one’s allegiance to that particular nation’s Constitution. For immigrants becoming naturalized citizens of the United States, the Oath of Allegiance frequently takes place at a citizenship ceremony.

The Oath of Allegiance is as follows:

"I hereby declare, on oath, that I absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty of whom or which I have heretofore been a subject or citizen; that I will support and defend the Constitution and laws of the United States of America against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I will bear arms on behalf of the United States when required by the law; that I will perform noncombatant service in the Armed Forces of the United States when required by the law; that I will perform work of national importance under civilian direction when required by the law; and that I take this obligation freely without any mental reservation or purpose of evasion; so help me God."

With prior permission, the U.S. Citizenship and Immigration Services will sometimes allow individuals to take the Oath without the following phrases: ". . .that I will bear arms on behalf of the United States when required by law; that I will perform noncombatant service in the Armed Forces of the United States when required by law.” U.S. Presidents also take an Oath of Allegiance, commonly referred to as an Affirmation of Office. It is mandatory for the incoming president take the Oath, and the wording of the Presidential Oath is in accordance with the U.S. Constitution. The Oath of Allegiance for United States presidents is as follows:

"I do solemnly swear (or affirm) that I will faithfully execute the office of President of the United States, and will to the best of my ability, preserve, protect and defend the Constitution of the United States."

In other countries, the Oath of Allegiance varies. For example, in England, clergy take an Oath of Supremacy, in which they swear the allegiance to the British monarch. In the Netherlands, members of Parliament swear their allegiance, such as:

"I swear (affirm) allegiance to the King, to the Statute for the Kingdom of the Netherlands, and to the Constitution. I swear (affirm) that I will faithfully perform the duties my office lays upon me. So help me God almighty!"

Throughout history, many individuals, religious groups, and secular groups have refused to take the specific Oath of Allegiance that countries dictate. This opposition has previously resulted in turmoil and sometimes even imprisonment. However, legal reforms in England that date back to the 1700s have permitted individuals to make solemn affirmations instead of taking an Oaths of Allegiance.

The United States has always allowed modifications to the Oath of Allegiance. The USCIS permits individuals to modify the Oath of Allegiance if there is a conflict with one’s religious convictions. In regards to the Presidential oath, Presidents are given the option to take an “affirmation.” Interestingly, Franklin Pierce and Herbert Hoover are the only two U.S. Presidents who chose to take an Affirmation instead of an Oath at their Presidential inauguration.