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I was reading around page 477 in Crystal about the large amount of spelling variation that exists even in Received Pronunciation. I was struck by the fact that all but a couple of the presented examples of spelling variation were irrelevant to American English speakers (alright/all right, judgment/judgement, maybe amok/amuck). All the rest of them (aery/airy, anesthetize/anesthetise, aging/ageing, adieu/adieus/adieux, etc.) were only variant in the British standard. I wondered if British spelling is to some extent less standardized than American spelling, and why that would be. Part of it may have to do with the fact that American spellings are influencing British spellings at the moment, but Crystal notes that this makes up only a small proportion of British variant spellings.  On the other hand, it may be that Crystal is only talking about the British standard, and American spelling has its own non-overlapping list of variant spellings.