What part of "illegal" do you not understand?

1. Each State Party shall take effective legislative, administrative, judicial or other measures to prevent acts of torture in any territory under its jurisdiction.

2. No exceptional circumstances whatsoever, whether a state of war or a threat or war, internal political instability or any other public emergency, may be invoked as a justification of torture.

3. An order from a superior officer or a public authority may not be invoked as a justification of torture.

That's Part I, Article 2 of the United Nations Convention Against Torture -- a treaty signed on behalf of the United States in 1988 by Deputy Secretary of State John C. Whitehead, submitted to the US Senate for ratification by President Ronald Reagan, and ratified by the US Senate in 1994.

Here's Article 4:

1. Each State Party shall ensure that all acts of torture are offences under its criminal law. The same shall apply to an attempt to commit torture and to an act by any person which constitutes complicity or participation in torture.

2. Each State Party shall make these offences punishable by appropriate penalties which take into account their grave nature.

And just to top it off, here's a little piece of the Constitution, internal emphasis mine:

This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.

I've looked high and low for the "torture works" exception and it seems to have been mislaid.

Time to get with the orange coveralls and leg irons, people.