University of Cincinnati Law Professor Sean Mangan does not hate many things, but ‘and/or’ has to be first on the list – along with whomever might be playing his Irish that weekend. I had the pleasure of taking multiple drafting classes with him several years ago, but I honestly never quite understood the depth of his anger towards the use of ‘and/or’ (along with “thereof”, “henceforth”, “hereto”, and the like). However, as it turns out, he is in very good company, as many judges and legal drafters seem to have some unresolved anger issues with this phrase as well.
The generally agreed upon meaning of “X and/or Y” is “X or Y or both”. That is a fine definition, but the problem is that the lack of clarity on the surface of the expression can allow opposing counsel to deliberately misinterpret whatever provision is in question in their client’s favor. If “X or Y or both” is what you mean, then just write what you mean! Take a look at how judges and style guides view the use of ‘and/or’: