hermandez

The advice fuzzylogician gave is very good (see fuzzylogician, on 18 July 2011 - 12:47 AM). Talk to people, network, get involved in a project with people outside of your institution that are attractive and that nobody has links to - this will give you some power. Discuss your work with others and if possible communicate it to outside audiences. Make sure your "supervisor", the s.o.b., knows about your actions. Don't confront him/her, at least until you are on more stable ground. Don't give the impression you are doing this to escape is cluch. Play innocent - <<Ohh, that can't be possible because I've been discussing/presenting/working with so and so or at so and so>>. At the moment, you are taken for a fool, so you have some slack before he/she realizes you are acting (present yourself as an eager worker out of his/her control). Later you will have to turn your apparent innocence into apparent political competence and the s.o.b. will slowly start to respect you.

As far as I know, at the schools I've been to, there is no difference between being a TA as an MA or PhD student, in terms of the concrete job responsibilities. Both 'kinds' of grad students are often assigned to the same course, so the duties would be the same, though sometimes there will be a 'Head TA' position which carries a little bit of extra responsibility. There may very well be qualitative differences, though, in the way you present yourself, the way students and colleagues see you, and how you choose to run your sessions within the leeway of the course.