"Inure," "enure," and the law

Though my family is full of lawyers, I had never heard the legal use of "inure to" until I found myself watching coverage of the George Zimmerman trial the other day, and heard commenters saying things like this (from the transcript of a discussion on CNN):

[Depositions before trial] yield a treasure trove of inconsistent statements. So, that always inures to the benefit of the cross-examiner, like a case like this. 

I knew inure only in the sense of "accustom, habituate," which the Oxford English Dictionary dates to 1489 (in its common alternate spelling, enure). But the legal inure -- "to take place, have effect; to be available; to be applied (to the use or benefit of a person)" -- is also well aged, dating to 1607. As for the spelling issue, "the form inure has now largely superseded enure," says the OED; "the latter, however, has a long independent history, and has been given separate treatment at ENURE v."

When we find ourselves with a word that has two separate but equal spellings, a common impulse -- at least among the orderly-minded -- is to assign them separate senses: mantel over the fireplace, mantle over the shoulders; insure for buying coverage, ensure for making something happen. But inure/enure has resisted such neatening; the people like inure, but the lawyers can't reach consensus.

H.W. Fowler wanted to tidy up by ditching enure entirely; he thought the word's etymology was so opaque that readers couldn't see the connection between the senses (and indeed, their link to Latin opera "work" is not obvious). Thus "there is a tendency to spell in- & en- for the two meanings as if they were two different words." They are not: "Variant spellings are therefore unnecessary, & -in is preferred by the OED."

But enure persists in legal writing, frequently enough that the website Daily Writing Tips hopefully suggests that "it may be useful to reserve the spelling enure for the legal term." That looks unlikely, since even Bryan Garner -- usage writer, lawyer, and language neatnik -- has no use at all for enure. In The Dictionary of Modern Legal Usage, he advises:

 No harm would come of abandoning enure; it wasn't the novel spelling that confused me about legal inure (I was listening, not reading), but the unfamiliar sense. Once I've learned that, context supplies the necessary clues. Similarly, I like using insure for both senses of the word, and though the tradition is fairly well settled now, it's hard to see that the mantle/mantel distinction contributes at all to clarity. But it's never easy for us natural-born sticklers to surrender our hard-learned editorial minutiae.