Now the real trouble begins as the case of Zacarias Moussaoui (search) hurtles toward a conclusion and the life of the admitted terrorist conspirator hangs in the balance.

Next comes the penalty phase in the criminal prosecution of the 36-year-old French citizen, who says the endgame of his flight training for 747 airliners was a strike on the White House, separate from the attacks of Sept. 11, 2001.

As chilling as Moussaoui's admissions are, international hostility to executions and the need for cooperation in President Bush's fight against terrorism raise an intriguing question: Does the Bush administration really want to put this man to death? The answer Friday was an unequivocal yes, as prosecutors basked in the glow of a victory that brought deep expressions of gratitude from relatives of Sept. 11 victims.

"As family members we thank you," Hamilton Peterson said in heartfelt comments to Assistant U.S. Attorney Ken Melson (search) outside the courthouse in Alexandria, Va., where Moussaoui pleaded guilty. Hamilton's father and stepmother died on United Airlines Flight 93 (search) in Pennsylvania.

Hamilton praised the president's "ever-vigilant efforts."

The Moussaoui case looks a lot different overseas. The European Union condemns the death penalty for foreign nationals in the United States. France, Moussaoui's country of origin, urges that he not be subject to execution.

German authorities have expressed reluctance to turn over evidence they had about Moussaoui because of concerns regarding his possible execution. Spain has said that it would not extradite terrorist suspects to the United States if they could be executed.

"Seeking the death penalty in the Moussaoui case always was going to be a very dicey choice," former federal prosecutor Larry Barcella said. In addition to Europe, the Muslim world "would basically view his being put to death as a public spectacle."

For critics of the president, the message of Moussaoui fighting for his life is that the Bush administration is paying no heed to international sensibilities against executions. To Americans, the prospect of Moussaoui as martyr or as a recruiting tool for al-Qaida means little.

"World opinion doesn't even weigh in on the scale," said Stephen Hess, a presidential scholar and political analyst at the Brookings Institution. "There is simply no way that public opinion in the U.S. would not overwhelmingly be for giving whatever the most severe penalty is. The rest of the world will go along on its separate track. It is not negotiable."

Despite admitting to six felonies, Moussaoui still can keep fighting in federal court, giving him an international stage.

Legal experts say he can highlight what he regards as the unfairness of it all, including his inability to call Sept. 11 planners as witnesses on his behalf in the proceeding that will determine whether he lives or dies.

He says the those planners would testify that he was not involved in Sept. 11. The issue barring his access to these witnesses was already decided before the planned criminal trial, which now will not take place.

"The whole world will be watching this penalty phase and it will be troubling to the judge that Moussaoui has no access to the al-Qaida detainees who might be able to help him," said Peter Margulies, a law professor at Roger Williams University in Providence, R.I.

Moussaoui can use only written summaries of interviews with those witnesses.

While admitting he was part of a conspiracy, Moussaoui can argue that his role sets him apart from others on Sept. 11. He did not hijack the planes and he did not direct the suicide crews.

"Everything about this case is different, it's a crime unlike any other in very significant ways and Moussaoui's involvement is different from any other death penalty case: He didn't kill anyone," former federal prosecutor Pete White said.