I have never met Sgt. Santos Cardona or Sgt. Michael Smith, but we share similar experiences.

In late 2003 and early 2004, both men used their dogs to intimidate Iraqi prisoners during interrogations at Abu Ghraib prison. They maintain that they were following legal orders. Now they both face impending court-martial.

From January 2004 to January 2005, I served in various places in Iraq (including Abu Ghraib) as an Army interrogator. Following orders that I believed were legal, I used military working dogs during interrogations. I terrified my interrogation subjects, but I never got intelligence (mostly because 90 percent of them were probably innocent, but that's another story).

Perhaps, I have thought for a long time, I also deserve to be prosecuted. But if that is the case, culpability goes much farther up the chain of command than the Army and the Bush administration have so far been willing to admit.

When the chief warrant officer at our interrogation site in Mosul first told me to use dogs during interrogations, it seemed well within what was allowed by our written rules and consistent with what was being done at Abu Ghraib and other detention centers.

The dogs were muzzled and held by a handler. The prisoners didn't know that, though, because they were blindfolded; if they gave me an answer I didn't like, I could cue the handler so the dog would bark and lunge toward them. Sometimes they were so terrified they'd wet their jumpsuits.

About halfway through my tour, I stopped using dogs and other "enhancements" like hypothermia that qualify as torture even under the most nonchalant readings of international law. I couldn't handle being so routinely brutal.

In training, we learned that all POWs are protected against actual and implied threats. You can never put a "knife on the table" to get someone to talk. That was clear. But our Iraqi prisoners weren't clearly classified as POWs, so I never knew what laws applied. Instead, a confusing set of verbal and written orders had supplanted the Geneva Conventions.

When an Army investigator asked Col. Thomas Pappas, the top military intelligence officer at Abu Ghraib, how intimidation with dogs could be allowed under this treaty, he gave the chilling reply, "I did not personally look at that with regard to the Geneva Convention."

Pappas later testified that he was taking his cue on the use of dogs from Maj. Gen. Geoffrey Miller, who took over detainee operations in Iraq after running them in Guantanamo Bay, Cuba.

Miller has denied recommending the use of guard dogs to intimidate prisoners during interrogations in Iraq. He also recently said he would not testify in the courts-martial of Cardona and Smith, invoking his right to avoid self-incrimination.

As someone who voluntarily spoke at length about my actions in Iraq to investigators, without a lawyer present, I can't have a favorable opinion of Miller. By doing the military equivalent of "taking the Fifth," he's decided to protect himself, apparently happy to let two dog handlers take the fall — a stunning betrayal of his subordinates and Army values.

Cardona and Smith have been accused of sick and sadistic behavior. They face the prospect of serious jail time. But they almost certainly acted believing they were following legal orders.

In the military, orders are orders unless there is clear, uncluttered law transmitted from far above our commanders' rank and station. Instead of a clear message prohibiting torture, our top commanders gave us a deliberate muddying of the waters.

Sen. John McCain, Republican of Arizona, recently shepherded a ban on torture through Congress. Then, while reluctantly signing the legislation, President Bush muddled this very clear ban on torture by stating that he would construe it "in a manner consistent with the constitutional authority of the president."

Those who serve in the prisons of Iraq deserve to know clearly the difference between legal and illegal orders. Soldiers on the ground need a commander in chief who does not seek strained legalisms that "permit" the use of torture.

The McCain amendment, prohibiting "cruel, inhuman, or degrading" treatment in all instances, is an accurate reflection of the true values of the military and American society. We should adhere to it strictly and in all cases.

I know, from personal experience, that any leeway given will be used to maximum effect against detainees. No slope is more slippery, I learned in Iraq, than the one that leads to torture.

Anthony Lagouranis served in the Army from May 2001 to July 2005. He wrote this commentary for The New York Times.