Hyphens, En Dashes, Em Dashes

Q. We are struggling with hyphenating trans-Atlantic and trans-Pacific. AP says to hyphenate; Chicago does not. But you say to hyphenate trans-American. If Atlantic, Pacific, and American are all normally capitalized, shouldn’t they all follow the same hyphenation standard for prefixes?

A. Chicago’s choices follow Merriam-Webster. If transatlantic and trans-American appear near each other in a manuscript, however, we might hyphenate both for the sake of visual harmony.