MADISON, Wis. — Every weekday as the clock strikes noon, dozens of demonstrators pass out songbooks inside the Wisconsin Capitol. Office workers who know what is coming scramble to close their doors, and several police officers take up watch from a distance.

Then the group begins to sing, the voices echoing throughout the cavernous rotunda. The first song might include the lyrics, ‘‘Hit the road, Scott, and don’t you come back no more.’’ The next tune could say, ‘‘We’ll keep singing till justice is done. We’re not going away, oh Scotty.’’