In a small saucepan melt margarine; stir in flour, onion, garlic powder, and red pepper. Stir in milk and broth all at once. Cook and stir until thickened and bubbly. Gradually add cheese, stirring until cheese is melted. Transfer to a fondue pot place over fondue burner.
Serve with bread cubes. (Add additional chicken broth, as necessary, for desired consistency.) Makes 6 servings.