I read the book in 1970 or so when I was in the Army, I thought the movie was pretty well balanced. The book starts with Huie visiting the "Dishonored Dead" section of the US Oise-Aisne Cemetery in France where Slovik was initially buried-his remains were repatriated in 1987. The author keeps asking why only one death sentence carried out and why Slovik, why if the purpose was to make an example of him was the execution carried out in secrecy. From there he goes into Slovik's troubled youth, his criminal record which initially protected him from the draft. But as the Drill Sergeant tells him and his fellow recruits in Basic, "You guys are the bottom of the barrel. But now the heat's one, Uncle Same needs bodies, and the bottom of that barrel is starting to look mighty good." Armies-and the governments they serve-have a funny way of lowering their standards as wars drag on. The official name of the Draft in the USA was (and is) Selective Service, by 1943 they were a lot less selective. Slovik was a good example of what WWII GIs called "The Sad Sack" (in my day, 1967-1971, a "dud", in civilianese we might say a loser.
One poster said Slovik gambled and lost, a very apt description. He repeatedly declared he would desert if given the chance, he was given a chance to redeem himself, he refused-I can clearly recall the scene where he tells the JAG officer "I want my court martial." Eisenhower hoped he could equal Pershing's record of no executions for desertion, but as the author notes he had a lot of other things on his plate. The author notes the court martial was made up of rear echelon officers, he notes the presence of some combat arms officers would have been better but they were otherwise engaged. I recall the scene where the president of the court reads the written secret ballots, realizes the vote is unanimous for death, tells the others "Let's have another cigarette and think about this."
Worth watching, very true to the source, this is one you watch and you draw your own conclusions.