With the end of the ideological rivalry between East and West, the world has a fresh chance to reinvigorate the idea and institution of collective security. Now that there is wide agreement on first principles, the United Nations can play the leading role its creators envisioned for it a half-century ago. An expanded Security Council, no longer paralysed by veto threats, can now become a more effective catalyst for UN action across a range of security and humanitarian needs. ____ .