I had a friend make the same mistake.
I had him recite the first few lines of the “Pledge of Allegiance.”
When he got to the line “And to the Republic, for which it stands...” He (gracefully) conceded the point.
You can find it on youtube. Just watch part 1 of “Jennie, Lady Randolph Churchill.” Jennie’s father “Leonard Jerome” even says in the film “I think you sometimes forget you’re the citizen of a republic.”