In what may seem like a bad joke, a U.S. federal appellate court has ruled that an illegal immigrant convicted of drunk-driving can’t be deported because federal immigration law discriminates against “habitual drunkards” like him. The case involves an illegal immigrant from Mexico, Salomon Ledezma-Cosino, with at least one drunk-driving conviction, possibly more. Ledezma-Cosino has lived in the U.S. illegally since 1997 and has eight kids, five of them anchor babies born in America. He works in the construction industry and has a criminal record. Ledezma-Cosino drank about a liter of tequila every day for a decade, according to medical...