Possessives and Attributives

Q. My 15th edition (7.18) cites “Kansas’s legislature” as an example, whereas 7.19 has “the United States’ role” as another. Am I correct to use “Paris’s sights,” “Philippines’ sights,” and “Seychelles’ sights” under 7.19? Could I also conclude that 7.18 is used mainly for states (like Kansas and Texas) in a country (like the US) and 7.19 strictly for countries?

A. The distinction is not between states and countries, but between names with a singular form (Paris, Kansas, Cyprus, Barbados) and nouns that take a plural form although they are singular in meaning (United States, Seychelles, Chicago Heights, Philippines). The singular forms make the possessive with the addition of an apostrophe and an s (Paris’s, Kansas’s, Cyprus’s, Barbados’s); for nouns with a plural form, add only the apostrophe for the possessive (United States’, Seychelles’, Philippines’).