Conspiracies — many faked, some veritable — have long enthralled Eco, from “The Name of the Rose” (1980), set in a medieval abbey where monks keep getting bumped off; to “Foucault’s Pendulum” (1988), about three book editors who invent a conspiracy theory that gets out of control; to his previous novel, “The Prague Cemetery” (2010), a portrait of a 19th-century malefactor who creates a notorious anti-Semitic forgery.

Eco’s predilection for cryptic truths traces back to his other career as a distinguished professor of semiotics, a branch of humanities whose practitioners are cursed to spend their lives explaining to strangers what they do. A central aim of the field is the deconstruction of human communications, reckoning with the unspoken codes and signification around us, from advertising to eating to the movies. Meanings are hidden everywhere, they argue — a view not far from that of the conspiracy theorist. Which is not to equate scholars with cranks. Only to note that Eco is professionally attuned to clandestine meanings, and to the risk of overinterpretation.

Another cause of Eco’s conspiratorial bent, I suspect, is Italy itself, where politicos have indulged in skulduggery since long before Machiavelli. Where conspiracies really do exist, is one nuts to expect them? When I arrived as a journalist in Italy a decade after Clean Hands, I was startled to discover that some people considered the villains of that scandal not the prosecuted but the prosecutors. Berlusconi himself routinely referred to the judiciary as flush with Reds plotting against conservatives like himself.

In the most stable of countries, scandals lead to disgrace, contrition (sincere or not) and resignations. In Italy, scandals are where history bifurcates, with parallel lines of explanation never to meet, disputed guilt, no crashing end and little regeneration as a result.

“Numero Zero” suggests that the interminable Italian political arguments over responsibility and blame trace back to World War II. “The shadow of Mussolini, who is taken for dead, wholly dominates Italian events from 1945 until, I’d say, now,” Braggadocio remarks. Of course, he’s a paranoiac. But is he wrong? Still today, Fascist and Communist graffiti blights walls across Italy, and Rome retains a prominent obelisk chiseled with the name of Il Duce. Imagine a Nazi-era tribute to Hitler in central Berlin today — it’s inconceivable. But in the Italian political opera, there are few finales, just encores nobody asked for.

Bogus or not, Braggadocio’s conspiracy theorizing leads to blood, which is perhaps Eco’s point: Fantastic claims have real costs. When Colonna feels imperiled, he takes to the arms of his young love interest, Maia. And she — previously a character more quirky than plausible — gains full voice, railing against the chicanery everywhere. “The only serious concern for decent citizens is how to avoid paying taxes, and those in charge can do what they like — they always have their snouts in the same trough.” She proposes running away to an even more corrupt country, where the venality will at least be in the open.

Colonna retorts that there’s no need to venture far. “You’re forgetting, my love, that Italy is slowly turning into one of those havens you want to banish yourself to,” he says. “All we have to do is wait: Once this country of ours has finally joined the third world, the living will be easy.”

Remember, this is 1992, when dirty hands were exposed and cleaner hands were to follow; all those perp walks and prison terms presaged a better domani. Enter stage right a dapper gent with a few trillion lire in his pocket and a satisfied grin on his chops. Berlusconi dominated Italian politics from 1994 until 2011, serving as prime minister three times. The Italy that he was to rescue is today one of dejection, unemployment, cynicism. Wanting to laugh, the impish Eco — along with many of his compatriots — is inclined to sigh at the state of his nation.