4 ideas
Filiberto García is an aging killer who has done the Mexican state's dirty work since the Revolution. Working through Chinatown, he finds the conspiracy is a fabrication run by Mexican insiders, and the young woman he falls for, Martita, is killed. He is left to clean up quietly, having been used and then discarded by the system he serves.
The PRI-era state depends on extralegal killers kept on call for murders that official institutions cannot acknowledge. Revolutionary legitimacy is the cover story; the working machinery is patronage, disposable muscle, and silence. Law enforcement and criminality are the same apparatus, told apart only by who signs the order.
When powerful insiders invent or inflate an external enemy, whether Chinese, communist, or foreign, they gain urgency, secrecy, and freedom from accountability. Great-power agencies accept the story because it fits their own paranoia. To find who benefits from a 'foreign plot', look first at the local officials who control its narrative.
The functionary-killer survives by obeying without asking questions. His cynicism, expressed through a constant profane verbal tic, is how he copes with knowing he is a tool that can be thrown away. That self-aware complicity gives him clear sight but no power: he can see through the system but cannot leave it.