The former diplomats and ambassadors signed the statement before the Friday debate between Obama and Republican nominee John McCain.

"We are supporting Senator Barack Obama because of his judgment, experience, and ability to inspire people to come together around a common purpose," the letter said. "Senator Obama's talents offer an historic opportunity; for the sake of America's security and standing in the world, we must seize it."

The letter, signed by officials from both major political parties, said the foreign policies of the Bush administration have diminished America's alliances abroad.

"As former diplomats, we believe it is past time that we had a President with the judgment and confidence -- in himself, our diplomatic corps, and our values -- to talk directly to America's adversaries with due preparation but without preconditions," the letter said.

The signatories include former secretaries of state Madeleine Albright and Warren Christopher, former National Security Adviser Richard Clarke and former U.S. Ambassador to Israel Martin Indyk.