Can a teacher push political views on students?

My nephew's high school social studies teacher talks very badly of Obama to her cles, many of whom are 18 and old enough to vote. If she was having discussions with them about candidates and views and policies, I think this would be great. However, she bases her facts on that ignorant m email that went out that Obama is a muslim, wants to put his hand on the Koran if he's sworn in as president, and that he refuses to put his hand over his heart when the national anthem is sung. I just have a huge problem with her spouting nonsense to these kids and have a mind to go down and have a talk with her. Keep in mind I don't even care for Obama and will not be voting for him. I still think she has no right to do this nonsense to 18 year olds that may not get any other info on him and base their vote soley on what she said. Can this teacher legally do this?