How Far Does Tenure Protection Extend?

In case you have not heard about the ruckus caused by University of Colorado’s Professor Ward Churchill, you can catch up on his views here. If you have the time and the inclination, you can read his entire article here. Much of the controversy that has resulted from his comments about 9/11 surround the pressures between firing the professor and the protection of his tenure.

The Philosophy department at CU Boulder has released a statement concerning the protection of his tenure:

The recent controversy over Ward Churchill's essay should not obscurethe fact that the precise purpose of the tenure system is to secure theability of university professors to argue the most unpopular of cases,in the face of the most heated public sentiment. We urge the Regents tohonor that system in its consideration of this case, and not to take anyaction that would threaten Professor Churchill's job or chill the freeexpression of thought that is so vital within a university community.

So, what exactly does and does not tenure protect? Many have found Churchill’s statements morally abhorrent, but they are on the loosing end of the current political and academic climate. What if his comments had been along the lines of, “all women should be raped”? Would his tenure protect him then?

I don’t know quite what to think about the entire situation-specifically what the protection of tenure does or should do. Please chime in with your take on this issue, and if you have direct knowledge of the ins and outs of tenure protection, please pass them on!

Update:
If you are interested in a response to Churchill's claim that the U.S. is morally, and thus, causally responsible for 9/11, see this critique at The Conservative Philosopher.