1997: President Abdala Bucaram, nicknamed "El Loco" ("the crazy one"), declared mentally unfit to rule after a year in powerThe first thing that strikes you is that they've actually bothered to translate 'El Loco' - as if nobody's ever heard Ricky Martin. But fair enough, there's no reason why people should go without handy news-nuggets just because they've been so lucky in other areas of life. But the main thing is, this is yet another clunky BBC translation.
What we've got here is the classic adjectival noun conundrum. Ask a Frenchman, or a German, or a speaker of any other Indo-European language I've ever come across, which socks they're going to wear or something, and they won't have to say "the grey ones". They can just say "the grey". Nor does it have to be that specific situation. It can mean "the grey thing(s)", "the grey person", or anything where the quality the adjective describes is all you actually need to get across. English can't do that, English has to add an extra word - 'one', 'thing', 'bloke' and so on - so English has no choice but to be more specific. Snappiness will be lost, and a nuance has to be added by the translator.
In this case, "the crazy one" not only sounds like a rubbish, rubbish political nickname, it also doesn't sound like a political nickname at all. It sounds like you're trying to explain to a friend which great-uncle you're visiting. Not the creepy one or the reclusive gay one, the crazy one, you know with the butterfly collection. Oddly enough, one of the few contexts where we do use adjectival nouns is historical nicknames. The Great, the Red, the Unready, we're used to it in this context.
So there are two ways this could be tidied up: "Abdala the Mad" - using the adjectival noun, just because we can, or "Abdala the Madman" - using a normal noun instead of an adjective. But neither of these quite capture how neatly this nickname seems to work in Spanish. That's probably just because I know most of my Spanish from westerns and gangster movies though.