the orb isn't there to protect anything other than its own purpose. The orb wouldn't have even been in the world of the Belgariad if not for The Accident.
It is Eriond who will restore peace to the World.
And as Necessity itself is more than powerful enough, it will certainly influence events to achieve the purpose of the Universe, whatever that may be.
From what you say evil genius, you think the Orb is now the equivalent of a Nuclear weapon. Belgarion's threat against anyone who dares to defy him or endanger peace. That is absolutely unnecessary. The Orb is monumentally powerful, but so is Belgarion, not to mention Belgarath, Polgara, Durnik, the Twins, and Beldin (should he retake human form) are more than deterrant enough.
Remember, Riva Iron-Grip and his descendents were the Guardians of the Orb, NOT the other way around.