...And Their Snotty Cousins, the Whoms

We just bought a replacement DVD of How the Grinch Stole Christmas. (Our previous edition met its demise last year and if you have children under ten in the home you are required by federal law to have a working copy on hand.)

On the back of the case is an unnecessary synopsis that includes this line:

The fun begins when the grumpy, grouchy, Yule-hating Grinch plots to ruin the Who's Christmas.

As we all know, of course, the Grinch is an ambitious serial offender who targets not just one Who, but the entire population of Whoville. That means we're dealing with a plural possessive, and it should be "the Whos' Christmas," with the apostrophe on the outside.

That's an easy one. But what about singular possessives that end in "S"? Should it be "Dr. Suess' holiday classic" or "Dr. Suess's holiday classic"? I'll bet not even those genial Whos in their most exalted moments of bonhomie would be able to agree on that.