Mr George W Bush has appointed Mr Henry Kissinger to lead an independent investigation of the government's failure to prevent the September 11th attacks.
"We must uncover every detail and learn every lesson of September 11," Mr Bush said before signing legislation creating the 10-member commission, which he initially opposed, and naming one of the most controversial US statesmen of the last half-century as its chairman.
Mr Bush said Mr Kissinger (79), a Nobel Peace Prize winner and secretary of state under presidents Richard Nixon and Mr Gerald Ford, would bring "broad experience, clear thinking and careful judgment to this important task".
But critics criticised the choice, citing Mr Kissinger's contested record during the Vietnam War and a US-abetted coup in Chile.
Mr Kissinger promised a full investigation, including an examination of any ties between US ally Saudi Arabia and Osama bin Laden's al-Qaeda network.
"We are not restricted by any foreign policy considerations . . . we are under no restrictions and we would accept no restrictions," Mr Kissinger said, adding that Mr Bush assured him that "he has every intention to carry out the recommendations of the commission".
Democrats, who appointed former senator Mr George Mitchell as vice chairman of the commission, said Mr Bush could be asked to testify in person about events leading up to the attacks that killed over 3,000 people. The White House rebuffed the suggestion while, Mr Kissinger skirted the question.