If faculty members are tenured, (A) then they are very politically conservative (B).  —Premise

And none of our better teachers are tenured, (not-A) —premise, therefore, none of them are politically conservative.(not-B) —premise.

Attack: The arguer commits “failure to see other reasons” fallacy. The arguer means since our tenured faculty members are very politically conservative and none of our better teachers are tenured, so our better teachers are not conservative. As a matter of fact, there are a number of other reasons that are sufficient to bring about politically conservative in addition to tenured, which means that tenured may be  sufficient but not necessary for politically conservative being true.