U.S. Practiced Torture After 9/11, Nonpartisan Review Concludes

[Fortinbras Armstrong]

5. Yes, torturers should be imprisoned

Torture is prohibited under 18 USC § 2340. See See also § 2340A, which says that those who order the torture are just as culpable (note: I tried to link to this, but the link would not work). I should mention the Supreme Court case of Wilkerson v. Utah, 99 U.S. 130 (1879). Justice Clifford, in delivering the opinion of the Court, said:

Difficulty would attend the effort to define with exactness the extent of the constitutional provision which provides that cruel and unusual punishments shall not be inflicted; but it is safe to affirm that punishments of torture, such as those mentioned by the commentator referred to, and all others in the same line of unnecessary cruelty, are forbidden by that amendment to the Constitution.

(The "commenter" is Blackstone.)

There is also the UN Convention Against Torture, to which the US is a signatory. See in particular Article 1 and Article 16.

Actually, should Khalid Sheikh Mohammed get his day in court, virtually all evidence against him will have to be thrown out because it was obtained under torture. See Brown v. Mississippi, 297 U.S. 278 (1936) for the legal precedent. Thank you, Bushmen.