Ajahn Khemasanto, abbot of Wat Dhammasala in Perry, Mchigan, has said that having a glass of wine with dinner (for a lay-follwers at least) does not violate the fifth precept as long as one stops before they can "feel the effects" of the alcohol. The main reasoning behind this interpretation, I suppose, is the intent of the precept itself, i.e., the precept to refrain from intoxicating drinks and drugs that lead to carelessness is meant to help protect one from breaking the other four precepts, not to insinuate that drinking alcohol in and of itself is unwholesome. Whether this is what the Buddha himself meant when he formulated the fifth precept, I do not know; I am just passing along what I have heard. I myself have a glass of wine once in a while, and I do not lose any sleep over it. Suffice it to say that I am not a strict "Theravadin." I tend to follow the spirit rather than the letter when it comes to doctrine.
"Sabbe dhamma nalam abhinivesaya" ().
(non-Buddhist related blog)