Difference between “presidentship” and “presidency”

Question

What's the difference between presidentship and presidency? Please give examples to show the difference.

Answer 1

Four dictionaries I consulted gave presidentship as a synonym of and definition for presidency. Both appear to mean the office, tenure or term of a president.

Presidentship is a regular formation for a noun with this meaning, adding -ship to the title of office.

However, I have never encountered the word presidentship; and upon Googling the word and tracking hits through ten pages I found it used only in a) dictionaries, b) a few personal posts by persons who are evidently not native speakers and c) a fairly large number of pages about Indian politics.

I conclude from this that there is no difference in meaning between presidentship and presidency, but presidentship is the preferred term in Indian English, presidency in other English speech communities.

EDIT:
@Kris suggests that “presidentship comes in very handy where you need to refer to that state while distinguishing from the office,” and cites Wikipedia s.v. Edward Martin(Queens’ ). That distinction would indeed come in handy; but the passage in question does not draw it. The facts to which it alludes are that Martin was arrested and removed from the state of exercising his office on August 30, 1642, but was not removed from the office — as Wikipedia puts it, “ejected from the presidentship of Queens’ College” — until March 13, 1644. (Grey, The Queens’ College (1899), pp. 163, 171).

Presidency and presidentship have historically been in free variation. Indeed, Mullinger, University of Cambridge from the Earliest Times ... (1873) uses both on the same page (446), with no evident distinction: “[Fisher's] election to the presidency of Queens’ College”, “when [Fisher] resigned the presidency”, and, in a footnote, “[Wilkinson] succeeded Andrew Doket in the presidentship in 1484”. So also Thomas Thomson, History of the Royal Society (1812) page 12: “the presidency of Martin Folkes, Esq.”, “the presidentship of the Earl of Morton”, “the presidentship of Sir John Pringle”. Modern writers appear to have achieved greater consistency by restricting themselves to one term or the other.

Answer 2

Presidentship has a long history, with an earliest citation in the Oxford English Dictionary dated about 1525, and the most recent one dated 1986. That, however, is from the ‘Times of India’, and the only other twentieth century citation is from a letter by Nehru. The definition given is ‘The office or function of a president, presidency; the fact of being a president; (also) the period during which a president holds office’, which is almost exactly the same as the definition give for presidency.

Corpus evidence does not support its current use in either British or American English. There are 1098 records for presidency in the British National Corpus and 9959 in the Corpus of Contemporary American English. There is none in either for presidentship.