One Small Voice by Bob and Jan Young (1961)

Gina Morgan's ambition was to be an opera singer. All her spare time was spent in practicing, till suddenly, in her senior year, she realized that her music had become a wall that had shut out friends and the stimulation of school activities. She auditioned for the lead in the Granada High operetta, hoping in his way to achieve popularity, but another girl won the role! Gina's world shattered, and the year which should have been happy and challenging was dull and dateless.

The, miraculously, Walt Kennedy asked her to the Valentine Dance, but the most wonderful evening in her life ended in misery. Walt's care collided with an improperly park car and he was forced to pay a bribe. For the first time Gina was made aware of city corruption. She had never been remotely interested in politics; now she found herself boiling mad. There ought to be something she could do, but how could one girl alone fight graft?

The answer came when her class in American Government decided on a campaign to get out the vote. Nobody wanted to head the project, and Gina saw it as her one chance to salve her wounded pride and gain her classmates' respect. Her Future Citizens Committee were only teen-agers, but perhaps democracy needed fresh young blood to make it all work. Walt seemed impressed as Gina planned her all-out campaign, and she found herself making new friends and gaining new confidence. Her triumph and that of the Future Citizens came on election day when their car pools, teams of baby sitters and good citizenship banners for every voter resulted in the biggest election turn-out in Granada's history.

For Gina the victory was greater than just the town election. In teaching the townspeople that an ideal is worth working for, she discovered that no dream or ideal has value unless you are willing to work for it. Armed with this knowledge, she was able to judge honestly her own musical aspirations and decide on her own future. (from the inside flap)