English to Japanese Social Sciences Government / Politics

前後の文章は少し長いですが、こちらです。
Having reached the above conclusions, it is also incumbent on the Commission to consider the question, while there was no deliberate targeting of civilians by the Security Forces, whether the action of the Security Forces of returning fire into the NFZs was excessive in the context of the Principal of Proportionality. Given the complexity of the situation that presented itself as described above, the Commission after most careful consideration of all aspects, is of the view that the Security Forces were confronted with an  unprecedented  situation  when  no  other  choice  was  possible  and  all  ‘feasible   precautions  that  were  practicable  in  the  circumstances  had  been  taken,’  it  further  said.”
「比例の原則」と辞書検索をすると出てきますが、ここでは違うような気がしまして、適訳が分かりません。