Arkansas' Sibilant 's' (Salerno)

Do you have good grammar? Not so much? You can always become an Arkansas lawmaker and change grammar. I quote from NPR today that

Rep. Steve Harrelson, a Democrat in the Arkansas legislature, yesterday introduced a resolution to declare the correct way to write the possessive form of the state's name. That would be, he says, "Arkansas's." ... Not everyone agrees, however, including the largest newspaper in Little Rock, the Arkansas Democrat-Gazette. The daily stands by the Associated Press stylebook, which mandates that the state's possessive form is Arkansas'

There, see? The Arkansas Democrat-Gazette says he's wrong. Nice correction NPR!