‘Writing this book,” Matthew Brzezinski declares, “made me grasp the horrors of the situation’s choices.” The “situation” is the Nazi-ruled Warsaw Ghetto, portrayed with gritty detail in Isaac’s Army. From 1940 on, a 24-year-old Zionist youth leader named Isaac Zuckerman risked his life to organize armed Jewish resistance amid intrigue, betrayal, raw fear, and mass death. When Brzezinski first arrived in Warsaw as a young journalist, he wondered how he would react in the same situation, and confesses, “I used to see myself as heroic like Isaac.” But years later, when he returned as a husband and father, he realized the issue is more complex: “Almost everyone in the resistance was young and had no dependents. For older people, picking up a gun meant abandoning their families to almost certain death.”

How did you find out about Isaac Zuckerman?
Through his memoir. It made me wonder, what was it like to be alive then in this place? The city was totally destroyed by the Nazis, so to find out what it looked and felt like, I studied prewar books and magazines, and interviewed survivors. I wanted to show the rich textures of life in the ghetto, because we need to understand that to understand what happened there.

What triggered Isaac’s advocacy of armed resistance against the Nazis?
Isaac led one faction of the severely divided Zionist youth movement. The elders didn’t have any use for these kids. The general belief was, if we work with the Germans we’ll all be better off. So the Jewish council created its own law enforcement body, which was seen as a much better alternative to having SS thugs or their Ukrainian auxiliaries crash around the ghetto. In April 1941, the Jewish police raided Isaac’s “clubhouse” to collect slave laborers for the Germans.

What did Isaac do?
He complained to the elders and got into a fight, so they sent him to a labor camp on the Soviet-German border. Zivia Lubetkin—his co-conspirator, girlfriend, and eventual wife—sent one of her top female couriers to find out what happened. Because the courier looked Aryan, the German guards concluded Isaac was connected to the much larger gentile Polish resistance, which they didn’t want to antagonize for fear of reprisals. In May the Germans let him go—after putting him through a mock hanging. Isaac returned to Warsaw convinced the labor camps were death camps—and that resistance had to escalate.

What made the ghetto factions finally agree on that?
The Grossaktion: the mass deportation of Jews from Warsaw in summer 1942. Within weeks the Germans had taken 400,000 Jews from the ghetto by train to Treblinka’s ovens. That’s when real armed resistance was born. In October, the Jewish Fighting Organization, with Isaac as a key leader, became the ghetto’s supreme authority. The next task was to get weapons. That wasn’t easy, since so many black marketers were Gestapo informers. The Jews tried to link up with the Polish resistance, but many of its factions were vehemently anti-Semitic and others wondered why they should arm Jewish teenagers when they were short of weapons themselves.

How did Isaac get around that?
He hooked up with the Jewish resistance in Krakow, the seat of the Nazis’ colonial government. Unlike in Warsaw, there the Germans felt comfortable, making them vulnerable. Isaac’s audacious scheme was to bomb cafés popular with the Ger-mans at Christmastime; it would create a diversion while Jews raided the arsenal. They would shock everybody, kill a few Germans, get a few weapons, and get away. But the Gestapo had infiltrated the Krakow resistance and set up an ambush. Isaac was shot in the leg. He was bleeding profusely. His contacts were blown. The Gestapo was hunting him. He was alone, left to die on a staircase. But children living in the building took pity on him and brought him their Christmas treats. He made it back to Warsaw in January 1943.

What did he discover?
The only Jews left were 60,000 slave laborers, alive only because they sewed uniforms for the Wehrmacht. But the SS decided to thin the Jewish population again. Enter Mordechai Anielewicz, the charismatic leader of another youth faction. Like Isaac, Mordechai pushed for armed resistance. He had the first guns and was eager for action. As the Germans took groups of Jews to the train station, he and his comrades walked with them; each killed the German next to him. The Germans were stunned and gave up corralling Jews. This galvanized the Jewish resistance. And it convinced the Polish resistance that Jews weren’t passive, so they shipped them handguns and 50 rifles. It was a pittance against the Waffen SS, but these Jews felt shamed from passively watching the Grossaktion; they would have fought with their bare hands. The Poles also trained them to disassemble plumbing and pack it with explosives—what we’d call IEDs.

How did they plan to use those?
By leaving few gates in the ghetto walls, the Germans had created choke points for themselves. Isaac and Mordechai realized they could use explosives and incendiary devices—planting them under streets, showering them from buildings—to hold the Germans off indefinitely. In April 1943 they prepared a trap. But they disagreed about strategy. Isaac wanted to dig underground bunkers—bases they could use to hit and run and hide. But Mordechai was sure they were all going to die anyway, so he wanted to inflict maximum casualties. For that you needed height. His plan used rooftops and attics, tunneling through walls so people could change positions without being seen. Initially this was tremendously successful; the Germans were sitting ducks.

How did the Germans respond?
The SS commander, General Jürgen Stroop, realized he had to burn the ghetto down or risk a mini-Stalingrad. Without higher ground, the tide turned quickly. Mordechai and 80 of his fighters committed suicide. But his strategy meant disaster for Jews who wanted to fight—not die in a modern Masada [where Jews made a suicidal last stand against the Romans in the 1st century].

Where was Isaac?
On the uprising’s eve, he was sent outside the wall as an envoy to the Polish resistance. He was ripping his hair out: he saw the smoke, heard the explosions. He knew his friends and Zivia were fighting and dying. He and his 15-year-old bodyguard managed to pull out about 50 of the 500 fighters through the sewers.

With the ghetto leveled, where did the rebels hide?
The Jewish partisans had a big problem. Isaac could pass for an ethnic Pole; Zivia and most others couldn’t. Most escaped into the forest. Zivia hid in a Warsaw closet with several other leaders. Except for Isaac, they couldn’t even stick their heads out to have a cigarette. There they waited until summer 1944, when the Soviet Army neared the city and the Polish Home Army began the Warsaw Rising. We know how that turned out: 200,000 Poles died and the city was destroyed.

Did Isaac’s tiny band join the uprising?
They heard the fighting, broke out of their closet, picked up weapons, and shot at Germans. They were elated. But because the Polish resistance didn’t tip Isaac off about the uprising, they fought with the Soviet-backed People’s Army instead of the Home Army. After the fighting ended, the half-dozen survivors hid, listening as German sappers leveled the city, house by house. They escaped through the sewers to hide in the forest until January 1945, when the Soviets rolled in. The NKVD summoned them to meet with a general. He was drinking toasts to them. They were stunned. Their People’s Army trench mates were now government ministers.

How did Isaac exploit that?
Some 250,000 Polish Jews survived the Holocaust by fleeing to the Soviet Union; now they were back. Many wanted to go to Palestine, which the British were blockading against Jews to avoid an Arab revolt. The  Soviet-backed Polish government didn’t want trouble with the British, but in 1946, it tacitly allowed Isaac to set up a back-door route for emigrants to Palestine. Isaac, the last to leave, joined Zivia and their newborn child there.