Q. Is it JD Vance or J.D.? I’m having a dispute with an editor who claims to follow Chicago style and she insists on J.D.
A. In Chicago style, initials in a person’s name normally get periods; a nonbreaking space separates consecutive initials. Accordingly, our style would be “J. D. Vance”—as in a bibliography entry for the book Hillbilly Elegy, where the author’s name would be inverted: “Vance, J. D.” We’d add that space even though “J.D. Vance,” with periods but no space, is how the name is credited in that book (as in the 2016 Harper edition). (Unspaced initials with periods is a common style, though published books seem more likely to follow Chicago style, as this n-gram from Google comparing “T. S. Eliot” with “T.S. Eliot” suggests.)
But when initials are used alone, Chicago style says to use no spaces or periods, as in FDR (for Franklin Delano Roosevelt). And we make other exceptions—for example, for pen names (as in H.D., with periods but no spaces, for the poet Hilda Doolittle) or stage names (as in LL Cool J, no periods or spaces). So if Vance himself prefers “JD Vance” (i.e., without periods or spaces), as this Wall Street Journal article from July 17, 2024, suggests, then it’s OK to use that form, at least for mentions in the text. In a bibliography or reference list, on the other hand, you could follow Chicago style, assuming the cited sources themselves include periods (see also CMOS 13.75).