What the teacher did is WRONG WRONG WRONG!
So what if your kid would not do a good job! Even better for the other kids to see this and see they did not make the best choice - a learning experience for everyone. Reality!
And a learning experience for your daughter. If she did not do the job good, then she would learn they will not vote for her next time around. Or perhaps she will learn a bit of responsibility having such a position.
I would have marched down there with a quickness and insisted she be placed on the student council. I would also threaten legal action!
I would also suggest the teacher take a few lessons in the difference between democracy and dictatorships!
Here is some good info for you...
Electoral fraud - Wikipedia, the free encyclopedia
Democracy - Wikipedia, the free encyclopedia
Dictatorship - Wikipedia, the free encyclopedia