Ess, cee?

Seen a few days ago on The New Republic website:

"God on the Quad offers a bold prophesy but little reason to believe it."

Oops. Apparently someone never learned the simple rule that when there is a noun-verb pair of words identically spelled except that one takes a "c" where the other takes an "s", the noun is invariably the one with "c". Practise? Verb. Practice? Noun. It's not that difficult. There aren't even that many of them:

Advice/advise
Device/devise
Licence/license
Practice/practise
Prophecy/prophesy

I'll concede that the licence/license pair has vanished from North American English: "license" now serves us for all purposes, noun and verb alike. There are also signs that "practice" is headed in the same direction, and it's easy to see why: "practise" and "practice" have identical pronunciations, making the distinction almost academic.

But "prophesy" is not a noun. It isn't even pronounced the same as "prophecy"; like the first two pairs, the terminal vowel sound changes, making it a distinctly different word. It's beyond me how an error like this can creep into a professional publication.