If you feel a professor is penalizing you for your political views
Check if the syllabus or the university has a policy on contesting grades.
KNOW YOUR RIGHTS
Students are typically not entitled to the same kind of academic freedom that professors are, but they should be given the latitude to explore a broad range of ideas and should not be penalized for their political views.
If you are expressing views that you know will be controversial or are contrary to accepted truths in the academy, it is particularly important to ensure that your arguments are well thought out. Make sure that your methodology is sound, your evidence is strong, and that your point is well-reasoned. It may be helpful to discuss a controversial thesis with a professor prior to completing an assignment.
As teachers, faculty members can and should provide substantive feedback to help improve your work. Try to evaluate your work objectively. Are your points well argued? Have you provided enough evidence for them? Are they relevant to the course? Have you fulfilled all the requirements of an assignment? Evaluate the feedback to determine whether there is a clear indication that the professor was biased.
Just as you have the right to express your opinion in the classroom, your professor and fellow classmates have a similar right to criticize those opinions. This can be an uncomfortable experience, but it is important to accept it as part of the learning process, and not in and of itself an inappropriate attack on your political beliefs.
Make an appointment to discuss your concern with your professor. Come prepared to defend each claim you make and to argue why your professor’s critique is unfair. Approach the discussion calmly and avoid resorting to personal attacks or criticism on secondary or unrelated matters.
If you feel unsatisfied with the outcome of the conversation, consider bringing the issue to the department chair or a relevant departmental committee. Be prepared to defend your points with the same rigor to which you defended them to your professor.