Ellen, in any situation it takes true courage to go against the mass of people. At US military, at least, you are instructed, as an enlisted man or woman, that it is illegal for you to follow illegal orders and that you should refuse to obey such and report the orders to higher authority.

Now, this carries with it the unspoken charge that you must a) be correct and b) are willing to accept the consequences of your action. Nobody likes a fink, and that is an attitude in every sector of life, not just the military. But consider that both Abu Graibh and My Lai were both originally reported by enlisted personnel and then think of the courage that took.

In the history of the US Army, there have been other (and much older, dating back to the 19th Century) times when enlisted personnel refused to obey wrongful orders. (I don't have my books here at work, but I can cite the situations after I get home if you'd like.)

    I went into a public-'ouse to get a pint o' beer,
    The publican 'e up an' sez, "We serve no red-coats here."
    The girls be'ind the bar they laughed an' giggled fit to die,
    I outs into the street again an' to myself sez I:
    O it's Tommy this, an' Tommy that, an' "Tommy, go away";
    But it's "Thank you, Mister Atkins", when the band begins to play,
    The band begins to play, my boys, the band begins to play,
    O it's "Thank you, Mister Atkins", when the band begins to play.

    I went into a theatre as sober as could be,
    They gave a drunk civilian room, but 'adn't none for me;
    They sent me to the gallery or round the music-'alls,
    But when it comes to fightin', Lord! they'll shove me in the                                     stalls!
    For it's Tommy this, an' Tommy that, an' "Tommy, wait outside";
    But it's "Special train for Atkins" when the trooper's on the tide,
    The troopship's on the tide, my boys, the troopship's on the tide,
    O it's "Special train for Atkins" when the trooper's on the tide.

    Yes, makin' mock o' uniforms that guard you while you sleep
    Is cheaper than them uniforms, an' they're starvation cheap;
    An' hustlin' drunken soldiers when they're goin' large a bit
    Is five times better business than paradin' in full kit.
    Then it's Tommy this, an' Tommy that, an' "Tommy, 'ow's yer soul?"
    But it's "Thin red line of 'eroes" when the drums begin to roll,
    The drums begin to roll, my boys, the drums begin to roll,
    O it's "Thin red line of 'eroes" when the drums begin to roll.

    We aren't no thin red 'eroes, nor we aren't no blackguards too,
    But single men in barricks, most remarkable like you;
    An' if sometimes our conduck isn't all your fancy paints,
    Why, single men in barricks don't grow into plaster saints;
    While it's Tommy this, an' Tommy that, an' "Tommy, fall be'ind",
    But it's "Please to walk in front, sir", when there's trouble in the wind,
    There's trouble in the wind, my boys, there's trouble in the wind,
    O it's "Please to walk in front, sir", when there's trouble in the wind.

    You talk o' better food for us, an' schools, an' fires, an' all:
    We'll wait for extry rations if you treat us rational.
    Don't mess about the cook-room slops, but prove it to our face
    The Widow's Uniform is not the soldier-man's disgrace.
    For it's Tommy this, an' Tommy that, an' "Chuck him out, the brute!"
    But it's "Saviour of 'is country" when the guns begin to shoot;
    An' it's Tommy this, an' Tommy that, an' anything you please;
    An' Tommy ain't a bloomin' fool -- you bet that Tommy sees!
(lyrics also posted here - click)
It's always been a puzzle to me why people assume that everyone in the military share the same views as their leaders. I suspect it's because the leaders get the headlines and the grunts take the bullets and die, their own opinions about it unheard.