What is Academic Freedom and Tenure, and Why Do They Matter (e.g., for teaching about religion!)?

Should the administrators of universities, their alumni, or their boards of trustees have any say in what teachers teach -- for example, in classes about religion? Should they be able to control the classroom in any way?

What about the argument that university professors are brainwashing their students to follow their liberal agenda, while hiding behind "academic freedom"? Does the U.S. system of tenure allow professors to say whatever they want, safe in the knowledge that they can never be fired?

What IS tenure anyway, and why does it matter? These are some of the key issues we'll be addressing in this discussion of academic freedom and tenure.