This week's 90-9 vote in the U.S. Senate to ban "cruel, inhuman or degrading" treatment of prisoners by the military found a clarity of purpose and voice that eludes the Bush administration.

Behind all the shocking revelations of torture at Abu Ghraib prison in Baghdad and reports of abuse at Guantánamo was a bumbling confusion at the Pentagon and White House that tossed out long-standing rules as they demanded that interrogations yield intelligence. U.S. Sen. John McCain, R-Ariz., cut through the fog with a timely quote from an Army captain asking for unambiguous guidelines: "Give them clear standards of conduct that reflect the ideals they risk their lives for."

The young veteran of Iraq and Afghanistan had tried and failed to get answers up the chain of command.

Those sentiments were echoed by former Secretary of State Colin Powell, a retired four-star Army general, and 28 other senior military retirees, who also saw guidelines as potentially protecting troops if they became prisoners.

Sen. Lindsey Graham, R-S.C., a former judge advocate, noted, "If you don't practice what you preach, nobody listens."

Such rules of behavior project American values as powerfully as any oratory on the desirability of democracy and the rule of law.

The amendment that passed has been around since summer, but the GOP leadership had balked, saying it tied the hands of the executive branch. Eventually, even threats of a presidential veto could not keep this statement down.

The language is appended to a $440 billion military-spending bill. The White House has said the McCain-Graham amendment might be the first veto of the Bush presidency.

A veto would be a tragic mistake, as would the amendment's demise during House-Senate conferences on the competing versions of the military-spending package.

A powerful, bipartisan voice has articulated a basic statement of what is permitted and forbidden with detainees in U.S. control. A handful of words speaks volumes to the rest of the world.