The marriage of words and music is a peculiar business. Nouns and verbs can sit on this or that combination of notes and function efficiently enough. But the right combination of the two elements is transformative. Ira Gershwin liked to cite the old Encyclopedia Britannica definition:

SONG is the joint art of words and music, two arts under emotional pressure coalescing into a third.

There was nothing obligatory about the early history of “The Star-Spangled Banner.” Behind Key’s words lay a melody — the so-called Anacreontic Song — endlessly adaptable to the causes of its day, from the French Revolution to abolition to temperance and women’s rights. Only in the last century has the anthem’s tune become inextricably connected to Key’s lyrics, and the lyrics to the sturdy patriotism of baseball and flag raising.