911恐怖攻擊事件是戰爭行為還是犯罪行為？若是戰爭行為的話，則遭致美國拘禁的塔利班（Taliban）與基地組織（Al Qaeda）成員或是涉及此攻擊事件的人員，也就是戰俘了，必須依據國際人道法給予人道處置。若是犯罪行為的話，也就是罪犯了，自無適用國際人道法的爭論。然而，由於美國以軍事干預佔領阿富汗與伊拉克，拘禁「涉及」911恐怖攻擊事件或協助國際恐怖組織行動的個人，使得國際人道法是否適用產生爭議。就國際人道法的性質與演進而言，主要涉及的就是人道（humanity）與軍事必要性（military necessity）之間的平衡。然而，這平衡是如何達成與進行呢？此動態的平衡是以什麼作為運轉機制呢？就美國政府的實務經驗而言，立法部門藉由立法授權行政部門以命令建立平衡機制，但最終是由司法部門的司法（釋憲）審查確立此平衡機制，美國政府的三權分立制度使得國際人道法的人道原則能在危機時期發揮平衡軍事必要性的作用，並確立國際人道法亦適用於無國家主權地位的恐怖組織。

The 911 terrorists' attack was a conduct of war or a conduct of crime? If it was a conduct of war, the detention of Taliban's and Al Qaeda's members or suspects who involved in the attack will be the prisoners of war, and should be treated humanely according to international humanitarian law(IHL). If it was a conduct of crime, they were criminals and should be prosecuted by criminal law. Since United States occupied Afghanistan and Iraq by military intervention and detained those people who has involved or assisted the 911 attack, it caused the dispute of application of the IHL into issues. For the nature and evolution of IHL, the balance between humanity and military necessity is the crucial matter. However, where did the balancing mechanism come from and how did it work? Based on the practice of American experience, it come from the Congress authorized the Executive to create the mechanism, but eventually the Judiciary confirmed it by judicial review. The separation of powers made a possible to build the balancing mechanism between humanity and military necessity, and confirmed the IHL was also available to the terror organizations with no state sovereignty.