Around then, popular music, always a reliable witness, began to recount the stories of people transporting drugs beyond the Rio Grande. With each decade, the songs got more and more explicit. “Camelia la Tejana,” one of the most emblematic, is about a woman whose car tires were “filled with the evil weed.” It ends with a shooting death. But soon, lyricists stopped killing off their antiheroes. Drug trafficking became an adventure story, or a comedy: in one famous song, smugglers disguised as nuns traded “white powder” they swore was just powdered milk.

Still, we didn’t think of drugs as our problem. In Monterrey over the years we sang about them, sure, we even smoked them — but we kept insisting they were only passing through, north to the Americans. We saw the construction going on in Monterrey, the new fortunes, and we knew the phrase “money laundering,” but we looked the other way.

After 9/11, the drug industry became harder to ignore. From then, day in and day out, the news media reported on the border: on interceptions of huge marijuana and cocaine shipments, dozens of deaths caused by warring gangs and stories of coercion and corruption among government authorities and policemen.

And still the habit grew, among the young and not-so-young, though it was always denied, never admitted. In certain neighborhoods here, it was said, absolutely anything could be gotten.