Shakespeare, in one of Nelson Mandela's favorite lines, now strangely apposite, says that "the valiant never taste of death but once." As the world waits for Mandela to make his final rendezvous with history, one woman — his third wife — who has been at his bedside throughout his illness, and now keeps vigil there, is almost perfectly cast for her role. Graca Machel (pronounced Mah-shell) has, after all, been here before.