Lehnert, who was appointed to open the Gitmo facility in January 2002, added that the candidates are reflecting the views of voters.
"If you want to make a claim towards American exceptionalism, you don’t make that statement without being truly exceptional. And torturing people is not exceptional," he asserted.
In recent months, Republican front-runner Donald Trump has advocated bringing back waterboarding terrorist suspects. He also told supporters at a campaign event that "torture works."
A 2014 ABC News-Washington Post poll revealed that 58 percent of Americans believe that the torture of suspected terrorists can be often or sometimes justified. The study also found that nearly two-thirds of US citizens believe that previous CIA practices of torturing terrorist suspects produced valuable intelligence.