Paris Nearly 60 countries signed a treaty on Tuesday that bans governments from holding people in secret detention, but the United States and some of its key European allies were not among them.
The signing capped a quarter-century of efforts by families of people who have vanished at the hands of governments.
"Our American friends were naturally invited to this ceremony; unfortunately, they weren't able to join us," French Foreign Minister Philippe Douste-Blazy told reporters after 57 nations signed the treaty at his ministry in Paris.
State Department spokesman Sean McCormack declined comment except to say that the United States helped draft the treaty, but that the final text "did not meet our expectations."
McCormack declined comment on whether the U.S. stance was influenced by the administration's policy of sending terrorism suspects to CIA-run prisons overseas, which Bush acknowledged in September.
Several other Western nations, including Germany, Spain, Britain and Italy, also did not sign the treaty.