The Constitution states that a president, among others, most take an oath or affirmation prior to taking office. Clearly there's a distinction between the two, or it wouldn't be phrased as it is.
What is an oath? One source claims that it is "A declaration made according to law, before a competent tribunal or officer, to tell the truth; or it is the act of one who, when lawfully required to tell the truth, takes God to witness that what he says is true. It is a religious act by which the party invokes God not only to witness the truth and sincerity of his promise but also to avenge his imposture or violated faith, or in other words to punish his perjury if he shall be guilty of it."
Clearly an oath has a religious component to it, an appeal to a higher--divine--authority.
What is an affirmation? From wikipedia: "In law, an affirmation is a solemn declaration allowed to those who conscientiously object to taking an oath. An affirmation has exactly the same legal effect as an oath, but is usually taken to avoid the religious implications of an oath. In some jurisdictions, it may only be given if such a reason is provided."
An affirmation seems to be an option for non-religious people. Something legally the same as an oath, but secular in nature.
It seems clear that the Constitution gives people the option to be religious or non-religious. I wonder if anyone in American history has taken an affirmation rather than an oath to hold public office? We do tend to state the people take oaths, not affirmations. Does public opinion push candidates in the direction of religiosity? What would we make of a candidate who choose to make an affirmation and refuse to take an oath?
Let's discuss this in class.