Different from a marriage, I would say. No electoral votes there: The oath is the thing. I always brace myself a little at a wedding ceremony, at the part where the man and woman say “I do” to a series of impossible-sounding promises. The place gets all quiet because everyone feels the same as I do. There is a difference in the configuration of the universe somehow, before and after that phrase. If the blushing couple were litmus test strips like we used in high school, they would change color at that point.

We took oaths as a kid. “Cross my heart and hope to die” sealed the deal. In the movie Stand By Me, which was mostly a true story of my generation growing up in the 1950s, even the hoodlum teenagers knew the necessity of oath-taking and, feeling the need to ratchet it up from “hope to die,” swore on their mother’s graves, which is the most solemn thing they could think of.

The oath Obama will take today comes straight from the Constitution, word for word. It was written and rewritten to get it just right, with un-prosaic balance-of-power concerns jostling behind the lovely prose. Somewhere along the line a president added, “So help me God,” for gravitas.

God took an oath to Abraham (Genesis 15). It wasn’t a formality. He set up a line of bloody, sliced animals and walked it, to show the earnestness of His pledge to do everything He had vouched to Abe. That’s what an oath is, actually—a self-maledictory promise to be put to death if you fail to fulfill your words. I wonder if Mr. Obama will be thinking of that as he raises his right hand today. It isn’t just a formality after all, is it?