The Washington Post
has an editorial about two foreign nationals on death row in Texas. The editorial is titled: Texas's Disdain
And refers to "Texas's death row".
According to the Texas Legislative Council Drafting Manual, that's incorrect. For possessives
To form the possessive case of a singular noun that ends in "s," add an apostrophe and an "s" to the word. If a sibilant occurs before the final syllable, adding an apostrophe and an "s" would make the word awkward to pronounce. To avoid a triple sibilant in pronouncing the possessive form, add only an apostrophe:
the alumnus's books
the witness's answer
Get with it, Washington Post
That's unfair. The Elements of Style instructs to append apostrophe-s no matter what, and I'm positive there are almost as many variations on the rule as there are rule manuals.
Yeah, Strunk & White for me.
German, and Old English, indicate possessives with an -es ending. The -'s ending indicates the omitted e, just as the apostrophe in don't indicates an omitted o.
So, Texases -> Texas's is valid historically, and no harder to pronounce than horses.
Strunk & White make an exception for Jesus' which just goes to show.