WHEATON, Ill.  Of all the reasons a beloved professor could be leaving the college where he has taught for the last 20 years, the one for Kent Gramm’s departure is peculiar: He is getting divorced, the college demands an explanation, and he refuses to give one.

So Dr. Gramm is packing up his office at Wheaton College, an evangelical Christian liberal arts school where everyone signs an agreement to uphold certain biblical standards of behavior, and divorce for reasons other than adultery and abandonment is grounds for firing. Rather than be fired, Dr. Gramm, a professor of English and creative writing, has resigned effective the end of this semester.

“Why are college administrators better able to judge my divorce than I am?” Dr. Gramm, who has been married for 34 years, asked in an interview. “If I had thought this was the wrong thing to do, I wouldn’t have done it.”

Dr. Gramm’s departure has prompted hand-wringing, a petition drive by students on his behalf and deep reflection on this peaceful campus about 20 miles west of Chicago, where visitors are welcomed by the towering pillars of the Billy Graham Center, named for the evangelist and 1943 Wheaton alumnus. Wheaton students vow not to smoke or drink on campus, and until 2003, they had to promise not to dance. (Now they can do so, but only if it is not “immodest.”)