In 1939, the pope ordered the death of Adolf Hitler.

Church of Spies by Mark Riebling tells the gripping history of the Vatican’s covert operations during World War II. A military plot had formed in Germany to depose the Führer, but there was a sticking point: what might happen to that country after Hitler was no more. The aftermath of World War I saw Germany punished severely, which helped spring Hitler to power in the first place. Nobody wanted a repeat of that, and so the conditions for mounting a coup were established: If the world promised a “just peace” for a de-Nazified Germany, the generals would go through with their plan and have Hitler killed.

The problem was a lack of assurances: Hitler’s enemies at home had no way of knowing if his enemies abroad would abide by the agreement. His enemies abroad, meanwhile, had no way of knowing if they weren’t about to replace one tyrant with another. The only person with the prestige and freedom to act was the pope, but asking the pontifex maximus for the go-ahead to put a bullet in someone’s brain was a tall order. Ultimately, not only did the pope say yes when approached, but he also established a robust intelligence apparatus and kept pushing parties to get on with it.

THE ECCLESIASTIC TELEGRAPH

Pope Pius XII’s relative silence during the Holocaust was criticized as both a moral failing and an inexplicable change of public demeanor. Before being elected pope, Eugenio Pacelli, as he was born, was a fierce critic of national socialism, sharpening his predecessor’s encyclicals and preaching racial equality. As pope, only his first encyclical during the war mentioned the Jews by name, and for such a fiery enemy of the Reich, he seemed to fall relatively—and inexplicably—silent on the issue. In fact, after the publication of that encyclical, as Riebling explains, “The last day during the war when Pius publicly said the word ‘Jew’ is also, in fact, the first day history can document his choice to help kill Adolf Hitler.”

Pius XII resolved to do whatever he could to have Hitler killed. His fellow plotters in Germany’s intelligence and military services asked him to keep quiet: “Singling out the Nazis,” later said one conspirator against Hitler, “would have made the German Catholics even more suspected than they were and would have restricted their freedom of action in their work of resistance.” The Catholic Church was a powerful resource to be leveraged. Though the Vatican lacks a formal intelligence service, during the war it possessed a de facto one: priests, monks, and nuns embedded in even the most war-torn towns in Europe, and their ability to secretly filter information to Rome, which could then disperse it widely or to necessary parties. In other words: The Church was a kind of ecclesiastic telegraph.

THE WAY OF SECRECY

Admiral Wilhelm Canaris / Årvasbåo , Wikimedia Commons

In the view of Hitler, Catholicism was incompatible with Nazism, as both asked for the whole of a man. Hitler hated Pius and the Church—Pius for his longtime stance against every element of national socialism, and the Church because it (accurately, as it turned out) couldn’t be trusted not to interfere with Nazi plans.

From the beginning, it was no secret that Hitler hated and mistrusted pretty much everyone, but when he ordered the “liquidation” of the Polish clergy after Germany’s invasion, it shocked even his generals. “The task I give you,” Hitler said to the group, “is a Satanic one … Other people to whom such territories are handed would ask: ‘What would you build?’ I will ask the opposite. I will ask: ‘What did you destroy?’”

The chief of German military intelligence, Admiral Wilhelm Canaris, witnessed the order. He already despised Hitler, but enough was enough: Hitler had to go. Canaris had known Pius XII from back in the 1920s, when then-Pacelli was a bare-knuckle Vatican diplomat in Germany. Pacelli, he knew, had three traits necessary to turn an assassination plan into action: realism, discretion, and a dislike of Hitler.

THE MANLY LAWYER

Canaris’s go-between would be a man named Josef Müeller, a lawyer, war hero, and devout Catholic known for representing Jews and opposing the Reich. Riebling describes him as “part Oskar Schindler, part Vito Corleone.” Müeller had once survived a personal interrogation by Heinrich Himmler, telling Himmler unapologetically that he had advised the Bavarian prime minister to have Himmler killed. (Word got around of the bold admission, which was a “manly” act, in Himmler’s words.) The SS head tried immediately, though unsuccessfully, to recruit Müeller for the SS, which needed men like him. When that didn’t work, out of apparent sheer admiration, he let the lawyer go. This made Müeller somewhat of a legend even among Hitler loyalists.

Müeller’s law office was a clearinghouse of information for the Vatican, where the lawyer was well-connected. Because of Müeller’s position in society both as a scholar and war hero, he was able to build a spy network among “army, college, and law-school friends with access to Nazi officials—a community of the well-informed, who worked in newspapers, banks, and even … the SS itself.”

German military intelligence knew of Müeller’s work with the pope, and brought him in for questioning. They first tried to recruit him, and when Müeller refused, they raised the stakes by admitting the unutterable: They didn’t want him to spy for Hitler, but for the opposite reason. “We even hope that someday you will be part of the leadership of this headquarters. The leadership of this Abwehr headquarters is, at the same time, the headquarters of the German military opposition to Hitler.”

He informed the Vatican of all this. Sensing the gravity of the plot brewing, the Vatican introduced to the German lawyer the concept of Disciplina Arcani—the “way of secrecy,” a doctrine established not long after the crucifixion of Jesus. “The faith at first survived only as a clandestine movement in Rome,” Riebling writes. “For three centuries, until Christianity became Rome’s religion, the Church concealed baptism and confirmation, the Our Father, the Holy Trinity and the Eucharist, the creeds and Scriptures—not only from heathens, but even from converts to the faith, who, as one later Church authority explained, ‘might be spies wishing to be instructed only that they might betray.’” This wasn’t an unreasonable precaution. All of the first popes were killed in ways that might only be described as gruesome, and over the centuries, 137 popes were driven from the city of Rome, dozens slain on Peter’s Chair.

THE TRIPLE BACKFLIP

The Abwehr established a cover for Müeller. Officially, he was to be a German operative using his contacts with the Vatican to spy on the Italians. His job would be to pose as a conspirator and sound out the Italian pacifists, who might cause Mussolini to go wobbly. He would even file reports for the Reich. “To all bureaucratic appearances, Müeller would advance the war effort by pretending to talk peace [with the Italians]," Riebling writes. "But he would only be pretending to be pretending. He would actually be the plotter he was pretending to be. He would be a plotter, covered as a spy, covered as a plotter. He would do a kind of triple backflip without moving a muscle.”

German intelligence presented Müeller with a dossier of Nazi atrocities in Poland, asking him to present it to the pope. “No one could more discreetly and credibly link Hitler’s internal and external enemies than Pius. As perhaps the most prestigious figure in Europe, above party pressures, he had the greatest advantage a ruler could possess: he was the one trusted power amid powers nobody could trust.” The pope could broker peace and convince Germany’s foreign enemies that a German resistance existed and could be trusted.

TYRANNICIDE

The Church is not philosophically opposed to “tyrannicide.” Writes Riebling, “over the centuries, Catholic theologians had developed a nuanced doctrine of tyrannicide, covering virtually every conceivable context.” Political violence was not allowed, of course, but if the assassination of a tyrant, among other things, promised to improve conditions in subjugated nations while not sparking a civil war, and if peaceful means were exhausted, then yes, go to it.

Pius began working in earnest with the German resistance, quickly bringing the British into the plot. (The pope’s codename among the resistance was The Chief.) He harried the British empire to accept a “just peace” for Germany and to maintain strict secrecy over the plotter’s doings; if word got out, good men would be sent to the gallows. The Vatican even put this in writing. Neville Chamberlain thus issued guidance to be relayed to the pope: “[Great Britain] would be willing to discuss any conditions asked for if convinced that business was meant.”

Catholic religious orders soon mobilized—especially the militaristic Jesuit and Dominican orders. They were doubly useful to the pope in that they did not report to local bishops, who might be found out or susceptible to Nazi pressure, but to order heads, who in turn reported directly to the pope.

For the expansiveness of the conspiracy to kill him, however, and the enthusiasm to see him dead, Hitler had “the luck of the devil” for surviving repeated assassination attempts and plans. He canceled speeches without knowing that positioned snipers were intended to take him out. He missed parades where bombers were set to blow him to pieces. Meanwhile, the longer it took for plotters to act, the less patience for such an act there was on the outside. Winston Churchill, upon becoming prime minister, put no faith in “decent Germans” acting to take out Hitler, and put little faith in the pope’s doings. It would be full scale war. Pearl Harbor later brought American patience to an end, and the United States into the conflict.

Plotters attempted again to kill Hitler, first by blowing up his plane (the bomb didn’t go off) and then attempting to kill him with a suicide bomb (the would-be assassin set the bomb for 10 minutes; Hitler left the area in three). A bomb sure to vaporize Hitler was brought for use during a secret meeting with the tyrant in his bunker. For no reason at all, however, Hitler changed venues to a cabin in the woods. When the bomb went off—only meters away from Hitler—those around him died, though Hitler escaped with only minor injuries. Hitler later speculated that he was immortal; in fact, he was spared because unlike a room in a sealed bunker, the cabin could not contain the blast. The fire and pressure instead blew through a nearby wall.

During all this, the SS zeroed in on the growing conspiracy against the Führer. Eventually, a member of German military intelligence broke, and he revealed the names of plotters involved. Müeller was placed under arrest, and his handler questioned. Worst of all, the conditions necessary for the German military to kill Hitler were discovered—printed on Vatican letterhead.

THE MARCH ON THE VATICAN

After the arrest of Mussolini on July 2, 1943, Hitler vowed revenge against the pope, and to have him kidnapped or killed. The pope and Vatican officials had worked feverishly to orchestrate a coup against Mussolini, connecting enemy forces internal and external, just as had been planned for Germany. In retaliation, Hitler ordered a division of paratroopers to the borders of St. Peter’s Square. “On one side stood German soldiers in black boots and steel helmets, with carbines on their shoulders and Lugers on their hips," Riebling writes. "On the other side were the Pope’s Swiss Guards, in ruffled tunics and plumed hats, holding medieval pikes in white gloves.” (This was not a case of bringing a knife to a gunfight; the Swiss Guard were also known to carry concealed machine guns.)

For his part, Hitler was ready to get things started. “I’ll go right into the Vatican,” he raved. “Do you think the Vatican embarrasses me? We’ll take that over right away. For one thing, the entire diplomatic corps are in there. It’s all the same to me. That rabble is in there. We’ll get that bunch of swine out of there … Later we can make apologies.”

His advisors apparently talked him out of an immediate invasion, though the following month, he summoned Karl Wolff, commander of the SS in Germany for a job of “world historical importance.” Wolff wrote at the time, “He wanted a study made of how troops could occupy the Vatican, secure the archives, and remove the pope, together with the Curia, so that they could not fall into Allied hands … Hitler would then decide whether to bring these Catholic dignitaries to Germany or intern them in neutral Liechtenstein.”

Wolff discouraged the plan, warning that if the pope resisted, he might have to be killed. Hitler didn’t mind, and ordered that plans be drawn up. Any chance at its execution, however, ended when the Allies liberated Italy.

AFTERMATH

In the end, of course, Hitler died by his own hand, but not before the SS systematically tracked down the German resistance, whose members were given the ultimate sentence. The SS interrogated them, tortured them, and sent them to concentration camps for extermination. Some were subjected to show trials before being publicly executed. Josef Müeller managed to survive multiple death sentences through happenstance, paperwork problems, and well-timed favors from well-placed allies. In the war’s aftermath, he would help found the Christian Democratic Union political party and credit the pope’s action and restraint for saving not only thousands of Catholics, but also thousands of Jews, and the resistance itself. It was the Vatican’s agents and allies who were so successful in everything from finding and leaking Hitler’s plans for German invasion of Belgium, to helping orchestrate multiple attempts on the tyrant’s life. And, as Church of Spies explains in extraordinary and well-documented detail, it all happened because Pope Pius XII had no qualms with killing the evilest man in the world.