Congress may resolve as early as Wednesday whether it's legitimate to use questionable interrogation techniques on terrorists who may know about plans to kill thousands of Americans

Some of those methods of interrogation could "shock the conscience" of Americans even if they are not defined as forms of torture. The White House and Sen. John McCain are struggling to find agreement over the treatment of detainees in U.S. custody before Congress breaks for Christmas.

McCain, R-Ariz., wants to amend two defense bills to ban cruel, inhuman or degrading treatment of suspects in U.S. custody. But the White House says it is calling for some flexibility with certain terrorists held by the CIA. The government faces the challenge of convincing high-value terrorists like Ramzi Binalshib or Khalid Sheikh Mohammed to talk when they are captured.

While critics may suggest otherwise, every U.S. government agency says torture is against U.S. policy and can't be used.

"Torture is defined, with reasonable certainty, severe pain and suffering, physical or psychological," said David Rivkin of the U.N. Subcommittee on Human Rights. "It is defined about as well as legal terms can be defined."

But the International Convention Against Torture also bans "cruel, inhuman or degrading treatment or punishment which do not constitute torture."

Those terms are not defined and while "cruel" and "inhuman" seem clear, many analysts say "degrading" could mean almost anything.

"If you apply it literally, it prohibits detention as such because it is absolutely degrading to be sitting, instead of running around and applying your trade of killing Americans, it is degrading to be sitting in a cell," Rivkin said.

In fact, one Muslim prisoner at Guantanamo Bay, Cuba, became very agitated when confronted by a female guard, something he considers degrading.

The Senate was so concerned about the vague language when it ratified the Torture Convention that lawmakers attached a reservation saying it interpreted "cruel, inhuman and degrading" as anything that would violate Supreme Court rulings, which prohibit any treatment of prisoners that "shocks the conscience."

Analysts argue anything more restrictive than that would tie interrogators' hands.

"If we are to rule out ... 'degrading techniques' to be used against prisoners or terrorists, then I think we could thoroughly dismiss any possibility of getting information about an imminent terrorist attack, period," said Steve Emerson, a terrorism analyst.

Some suggest other techniques to persuade terror suspects to share information.

"I think making somebody a little bit uncomfortable by making them cold, making them wet, making them listen to music they may not like to, make them stand up, keep them awake, that's a pretty long stretch from pulling their fingernails out or breaking their shoulders," said Lt. Col. Bill Cowan, FOX News' military analyst.

Waterboarding, a technique reportedly used with some effect on several key Al Qaeda captives, has also been used on U.S. troops during training.

"A waterboard is sort of like a ... see-saw. It's a board on a pivot," said former Marine Captain Nathaniel Fick. "So, I was strapped to the board and the board was rotated so my feet were above my head, and then a wet towel or a wet cloth was put over my face and water poured on that."

That method simulates the feeling of drowning and creates a sense of panic, and has left lawmakers also debating over whether that is illegal or not.