The national anthem of the United States is full of surprises, writes Mark Clague, a professor of musicology at the University of Michigan, in “O Say Can You Hear?: A Cultural Biography of ‘The Star-Spangled Banner.’”

Nearly everything about the 208-year-old anthem – from its meaning to how people sing it – has changed over time. Like America itself, the song is always evolving, Professor Clague tells the Monitor. The interview has been lightly edited and condensed. 

You point out that the first line is a question, not a declaration. Can you explain?

We don’t realize that the “O say does that star-spangled banner yet wave / O’er the land of the free and the home of the brave?” ends with a question mark, not an exclamation point. The song asks: Is the country still free? Is the flag still there?

It’s a question that gets renewed with every performance and constantly refreshes and changes depending on what’s going on. The song really highlights the notion of freedom and whether we have the courage as a country to try to live up to this ideal.