In the day of our Founding Fathers, honor was important in the character of a man. Men were careful about the oaths they took and they gave their lives rather than go back on their word.
When he joined the Navy, John Kerry took an oath. TheNavy Oath of Enlistment: "I, John Kerry, 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."
That oath lasted just four months.
The President of the United States takes an oath, too. It's mandated by specified in Article II, Section 1, of the Constitution: "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."
Since it was so easy to go back on his word when he served in the Navy, I wonder how long it would take him to go back on it as President of the United States. His track record on keeping his word isn't very good.