I couldn't care less ... or could I?

Two readers wrote in expressing their dismay over the misuse of this expression. Eager to clear matters up on their behalf, I began my quest to support their argument in favour of I couldn’t care less.

Lo and behold, I hit a roadblock, namely, The Concise Oxford Dictionary. While I couldn’t care less is indeed correct for use in Canadian English, apparently I could care less is its American English counterpart.

Does the American version make sense? I believe it does, my interpretation being: “I care about the size of a pinhead – if that, but yes, I suppose I could care even less if I tried very hard.” As derogatory as the Canadian version, wouldn’t you say?