He was the author of more than 20 books, including A People's History of the United States, a perpetual best seller.
Zinn's perspective on war was not created in a vacuum.
During World War II Zinn was a bombardier in the 490th Bombardment Group,
His targets included Berlin, Czechoslovakia, and Hungary as well as Royan, a seaside resort in southwestern France on which he dropped napalm.
He documented the last bombing in his book The Politics of History, the research included him discovering that 1.000 civilians were killed in that raid and the raid itself, ordered in the last three weeks of the war, was primarily a career-building exercise for the officers involved.
Many Vets share Zinn's feeling about their war experiences. Very, very few ever find a supportive platform to talk about their experiences and outlooks.
Even the best of generals/warriors throughout the ages have regarded war as a breakdown of politics/policy.
There is always another way, but it must be found before war is committed. Otherwise, a way must be found following the committing of the act of war. The war just makes it that much harder to accomplish.