Christian Doig’s review published on Letterboxd :
The onscreen meeting between Brando and Clift, the two defining actors of their generation, is akin to, for instance, the one of De Niro and Pacino in Heat, down to the frequency both pioneering champions of Method acting were related in people's minds and even mistaken for each other. As for the rest of the film, you can say that, also like with Michael Mann's production, The Young Lions is a most worthy narrative space, one which has a few interesting traits besides its stellar cast.
Director Edward Dmytryk, as efficient as ever in the delivery of a story full of conflict and human struggle --just remember Warlock or Broken Lance, two fine Westerns from the era--, takes a celebrated novel by Irwin Shaw and tells the intersecting stories of the German Christian Diestl (Brando) and the Americans Noah Ackerman (Clift) and Michael Whiteacre (Dean Martin) with the Second World War as their hugely impactful background. Diestl is an Aryan ski instructor with an eye for beautiful women; he is also one of the many people who fall for Hitler's promises, in his particular case of a future with a good job and economic stability, as Diestl sees himself in a precarious situation. Not a Nazi by any means, the arc of Brando's character will forgo an evolution almost similar to that of the officer played by Michael Moriarty in the miniseries Holocaust: the sensitivity of Diestl is open enough to destroy him in the process.
A morally stronger individual, definitely the most admirable figure in the whole tragic succession of events, Ackerman possesses a complexity of his own. Fragile like a feather, his inner strength makes him a victim of military abuse and the target of his mates. He is also a Jew, which is bound to bring him problems with the father of his girl, a sweet but dignified young lady (Hope Lange) who becomes receptive to Ackerman's boyish insecurities, awakening her motherly side. Make no mistake, though: if there is a man to look up to in the film is this vulnerable and yet incredibly brave person, and it is in the war field, even before among his bullying comrades from the company, that he proves it.
Whiteacre, a role suited to Martin even if his skills as an actor are somehow subdued by it, has to deal with other kind of moral circumstance. His dilemma consists on whether to go fight in the war or not, and there arises a conscience of his own potential cowardice --disguised as self-preservation or survival instinct-- that also begins to cause damage in his relationship with girlfriend Margaret (Barbara Rush), who is for her part torned between pushing him toward the danger of death that lies out there and protecting her lover --which would mean endorsing an unmanly image regarding him that she feels much unconfortable with. The role, apart from having a de luxe performer, serves two purposes in a basic way: first, to translate this so simple yet so familiar issue of courage versus cowardice, second, to link the other, main protagonists who are virtually polar opposites in the interlaced epic narrative: Whiteacre is Ackerman's best friend in the army --an inevitable reminder of Clift and Sinatra's warm comradeship in From Here to Eternity--, and Margaret has a brief liaison with Diestl on the eve of the War.
If the film works the way it does is mainly due to the screenplay and Brando's contribution. In the original source, Diestl was your naturally evil Nazi, and the actor changed that, risking the endeavour to fail completely. The fact that the bet --let's call it that-- paid off is part of what makes this a fascinating story. The innocence of Diestl turns his utter fall into an inescapable tragedy. Brando does it all in the subtlest of manners, and you can say that his job here is among his most underrated because of that. His scenes are all worth noting, but I'll mention the ones opposite Maximilian Schell and May Britt as they are specially significant to view how deep a toll the material and spiritual misery of the war takes of him. It is sad as hell.
On the other hand, Dmytryk makes a movie in which the horrors are often suggested rather than shown, even though he shoots some straight and rather grotesque imagery here and there, including the sequence featuring a too-slim Clift fist-fighting much bigger men or a disfigured Nazi officer all covered in bandages like a mummy from a horror genre movie. The black and white cinematography is striking and fitting to the shadows and ghosts that breathe along as Hitler and his evil schemes perish in the ruins of everything.