How I Survived Middle School: Madame President by Nancy Krulik

Jenny McAfee never thought of herself as a leader, but then again, Jenny had also never thought that her best friend, Addie Wilson, would ditch her for the Pops-the most popular kids in school. When Jenny's friends hear that Addie is running unopposed for sixth grade class president, they know they have to do somehting. That means convincing Jenny to put her name on the ballot. If Jenny and her friends can't keep Addie from winning, the Pops will officially run the school. But can Jenny really stop the Pops?