``They've never answered. From the record of this case they've ignored that it even existed,'' said Katherine Gallagher, a staff attorney at the New York Center for Constitutional Rights who is now collaborating with Spanish lawyers seeking Guantánamo prosecutions.

Her boss, Ratner, says news of the meddling may cause blow-back to the U.S. political effort.

``Now that it's been brought out that there were efforts to compromise the Spanish judiciary they're going to have to show their independence,'' he said.

Still unclear is how Martinez, a former trial lawyer, joined the effort to derail the investigation. Gonzales told The Miami Herald ``I had no knowledge'' about the activities of Martinez. Yoo said the same in an e-mail reply.

Neither would discuss the investigation itself.

Moreover, Gonzales argued it would be wrong to assume that Martinez, who quit the Senate four months later, was acting on behalf of any administration -- even though the cable describes the future banker as delivering the message to the foreign minister in tandem with Charge d'Affaires Arnold Chacon.

``Sen. Martinez may have been simply expressing an opinion or view,'' said Gonzales, who like the ambassador calls Martinez ``a friend.''

But a former Bush-era State Department official said, on condition of anonymity, that Martinez got a briefing from the Embassy each time he visited Madrid, either on a congressionally funded trip or as head of an influential Miami-based nonprofit, the United States-Spain Council.

KING CARLOS

Given his pedigree as a Bush insider and 2006-2007 Republican Party chairman, Martinez had greater access than most senators in Madrid. He would invariably offer, said the official, ``Is there a message you'd like me to deliver?''

If he agreed with the message, he'd convey it -- in visits that at one point took him to the palace to greet King Juan Carlos.

"Mel was loyal to President Bush and loyal to the people who were loyal to President Bush,'' said the former Bush-era diplomat. "He didn't look at whether it's the Bush administration or the Obama administration. He asked himself, `Is it the right thing to do?' ''