I rumbled down the stairs and hit the porch light. Then couldn't think of what to do that wouldn't result in a confrontation I couldn't win. If I'd been thinking more clearly, I would have put the dog on a leash and opened the door to have her bark at the bear from entirely too-close range. But I didn't. And the bear left after a disappointing meal of cat shit and rotten onions.
The cats, regal little jerks that they are, watched with only casual interest from the library bay window. Apparently "bear" is neither a threat nor a challenge the way another cat would be.
ETA: The bear looked WAY BIGGER to me last night, as I blearily stared out into the porch lights, than it had looked last week in the daylight - when I was looking down on it from the dining room window. Bigger nose, smaller ears. Upon a review of my horrible Ipad photos, no, no it's not. It's still maybe a 3-year-old. However, in afterthought, I think that sudden impression of size was why I decided not to do anything. That, and I thought the trash wouldn't be tasty. Judging by the evidence when I picked up the small pile (not strewn about the yard) of trash, I was wrong. Apparently bears will eat cat shit just like dogs.
So here's the horrible iPad photo with some re-touching for better contrast. Note that the bear's head is no larger than the watering can to his/her left, and nowhere near the size of the trash can lids that I threatened it with last week. Seeing where the bear stands as compared to the railing behind it, I maintain my theory that the bear is only somewhat bigger than mastiff-sized.