That risk cannot be totally eliminated, but it can be sharply reduced by conducting a series of test launches prior to the main mission.

FORBES: The Return of "Buzz Aldrin's Race into Space" Game

As Tom Ridge, America's homeland-security chief, has said, the threat can be reduced, but it cannot be eliminated.

ECONOMIST: Tense times at home

Though Serbia's change of guard has reduced the risk that Montenegro's own feuds will spark violence, it cannot be ruled out.

ECONOMIST: The Balkan jigsaw | The