In addition to innocent detainees who have been tortured to death, in CIA custody, or in military custody, and an unknown number of additional prisoners who are held by the United States in various undisclosed locations around the world, the US currently house 131 detainees in their Guantanamo Bay gulag who are not party to any criminal charges or investigations whatsoever, (innocent), a facility in which the United States have since admitted they used torture.
The "battlefield" does not constitute the whole world. In fact, a "battlefield" as its name implies, is where armed combat occurs. Combatants are those engaged in armed warfare. Abducted persons from non-belligerent countries do not classify, in any definition, as a "combatant" or a POW. Nevertheless, contrary to assertions made by the executive branch, the Supreme Court have ruled that their prisoners in Guantanamo Bay shall at least be afforded protections under the Geneva Conventions Common Article III, while they have not however broached the topic of the other prisoners in other locations.
Additionally, the "War on Terror", while making a great buzzword and catchphrase, is not legally classified as an "armed conflict" per any of the Hague or Geneva Convention treaties, nor is it a war legally declared by the US congress pursuant to Article I of the US constitution.
The continued policy for these unlawful detentions undermine US credibility, especially in their aim to preach human rights to other nations, breed continued resentment towards the United States which can lead to further recruitment in terrorist organizations, and of course, most importantly, constitute an egregious moral outrage, in my opinion.
Most importantly, these unjustified incarcerations violate the fifth amendment of the US bill of rights, which states that "No person...shall be deprived of life, liberty, or property, without due process of law..."