A Spanish judge has exposed a “sleeper” terrorist cell in Madrid and cast unique light on the worldwide radical Islamic conspiracy that has attacked the United States and other countries, threatens further assaults, and triggered military response starting with the invasion of Afghanistan, headquarters of the conspiracy.

The Spanish cell had operated since 1994, blending into local community life, according to a long and detailed indictment. The Syrian-born suspected leader had shaved his beard, married a Spanish woman, listed his name and address in the Madrid phone book, drove his children to school and generally established himself as a genial member of the neighborhood. But Spanish investigators, who had been watching him since 1997, traced his secret travels to confer with leaders of the al-Qaida network and raise funds through stolen credit cards. They monitored telephone conversations before and after the Sept. 11 attacks between cell members and a Hamburg apartment where some of the suicide hijackers stayed. After the attacks, one of the terrorist leaders told the Madrid cell, “We’ve entered the field of aviation, and we’ve even cut the throat of the bird.”

The arrest and indictment of the eight men in Madrid provides the most revealing account yet of how such sleeper cells are believed to be operating in the United States and in other countries, notably in Europe, awaiting orders to commit further terrorist atrocities. American investigators could find these prisoners a rich source of intelligence. But there has been a catch. Spain refuses to turn them over to the United States unless this country agrees to try them by a civilian court, not the special military tribunals recently ordered by President Bush. Other countries among the 15-nation European Union would probably insist on the same guarantees. The European nations also have all renounced the death penalty and could be expected to refuse extradition of suspected terrorists unless the United States agrees not to seek capital punishment.

European nations, while eager and effective members of the anti-terrorism coalition that Mr. Bush and Secretary of State Colin Powell have put together, are thus ahead of the United States in respect for civil rights. Mr. Bush and Attorney General John Ashcroft are adamant supporters of the death penalty, and Mr. Bush’s home state of Texas leads the nation in executions. The Spanish judge seems to know more than most Americans about the new system of military courts.

Contrary to some administration officials and media reports, the special courts would depart drastically from the Uniform Code of Military Justice, which applies to U.S. service men and women and prisoners of war in military custody. Unlike the special courts, this code requires a public trial, defendant’s choice of counsel, unanimous vote for a death sentence, proof beyond reasonable doubt and an elaborate system of appeals all the way to the U.S. Supreme Court.

There’s an old joke about a politician who sees a crowd rushing past. He says, “I’ve got to catch up with them. I’m their leader.” With the arrests in Spain, Mr. Bush has an opportunity to avoid that fate by catching up with the rest of the coalition.