The resignation of the 59 year-old prelate was offered under Canon 401, paragraph 2 -- i.e. the section of the law which deals with "because of ill health or some other grave cause."
Forgive me for being absolutely shocked.
For those of you who don't know the backstory, the Denver-born Bennett was mysteriously shipped off to the tiny inland Jamaica diocese in July 2004, after serving for six years as the wildly popular auxiliary bishop in charge of the Urban Vicariate of the archdiocese of Baltimore. Few knew what actually caused the unprecedented move to happen, but many were outraged; Bennett had become a widely-sought spiritual director and adviser to many priests and others. (Here's a good interview with him from shortly after his arrival in the Caribbean.)
Just the other day, I was on the phone with a friend who had been in recent contact with the bishop, and apparently everything sounded fine -- so fine that we mused on Bennett's possible appointment as archbishop of Kingston in succession to the 73 year-old Lawrence Burke, also a Jesuit.
The chances of that seem to be lessened now. And what's unfolding is anyone's guess.
As soon as I find out, I'll let you know.