An oath is defined by Merriam Webster as:
(1) : a solemn usually formal calling upon God or a god to witness to the truth of what one says or to witness that one sincerely intends to do what one says
(2) : a solemn attestation of the truth or inviolability of one’s words – The witness took an oath to tell the truth in court.
An oath is a sacred promise. While this might not carry as much weight today as it once did, it does for most of those who take an oath. It is a commitment that not only defines what a person agrees to do, but also defines who that person is.
Oaths are used for major offices, including members of Congress, judges, and other elected officials. For example, Presidents swear the following oath at their inauguration:
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.[
Commissioned and warrant officers in the United States uniformed services swear the following oath:
I, [name], do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God.[1]
Each person enlisting in an armed force swears to the following oath:
I, (state name of enlistee), do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; and that I will obey the orders of the President of the United States and the orders of the officers appointed over me, according to regulations and the Uniform Code of Military Justice. (So help me God).”
Those in the National Guard take similar oaths, adding their obligations to their state or territory.
The common factor is that the core of each oath is the commitment to the US Constitution. Those in the military are pledging their lives. I’ve seen enough inverted rifles, boots, helmets, and dog tags to know that those in uniform really mean it.
That’s what makes the US what it is.
sfnowak 
Thank you, Steve, for an excellent post that reminds us of the meaning of official oaths. As an American of Mexican parentage, I will never forget how proud my dad and mom were to be American citizens, and how seriously they took their oath to our country. They were contributors and givers, not
takers, for the whole of their lives.
When Judge Jellitich asked my mom her final citizenship question–“Mrs. Martinez, do you belong to any SUBVERSIVE organizations?”–and mom thought for a few seconds and then answered, “Yes, your honor.” I thought the entire courtroom was going into cardio-respiratory arrest…it was so quiet.
Mom said, “The St. Francis Altar Society, The Women’s Quilt Club, Guadalupana Prayer Group–and Judge Jellitich began laughing in hilarious orbit. And the whole courtroom joined in–all except mom, who didn’t know what was so funny.
Later that evening at mom’s celebration get-together, mom told all of us 13 brothers and sisters that she felt she was “BEING FREED”–becoming an American citizen. America is where people could believe in and advocate for individual rights, which was greater than big government. Work is opportunity
for all people to enjoy free enterprise–where the more enterprising people are, the FREER we are. America is a country with a limited federal government where people are focused on citizenship, opportunity, and BEING FREED to “meet life,” enjoy healthy relationships, and being personally and professionally fulfilled; a country grounded in the guidelines and protection of our Constitution, guided in the morality of God, and a people who are of high consideration for others and always grateful and thankful. So, unlike any other nation–America and Americans know that when they fight with one another, it’s the land, the country, that suffers.