Good luck trying to convince many Americans of that, though. Polls have shown a public generally supportive of the use of torture to gain information from terrorist suspects, at least in some circumstances, and even when you flat out call it "torture."
In 2009, the Pew Research Center found that 49 percent of the public said that "the use of torture against suspected terrorists in order to gain important information" can "often" or "sometimes" be justified. This belief was held by 64 percent of Republicans, 54 percent of Independents and 36 percent of Democrats.
Including the number who say that torture can rarely be justified, 71 percent of Americans accept torture under some circumstances.
Overall 25 percent of respondents said torture could "never" be justified. Fourteen percent of Republicans said the same, compared to 38 percent of Democrats.
While these figures are from 2009, a more recent YouGov poll from 2012 showed similar levels of support for torture among the public overall. A 2014 report by the advocacy group Amnesty International found that U.S. respondents were more supportive of torture than people in other wealthy Western countries.
UPDATE: Pew data from 2011 paints largely the same picture.