Notes and Rules Information for Circle of Protection: Red:
  • A source of damage is a permanent, a spell on the stack (including one that creates a permanent), or any object referred to by an object on the stack. A source doesn’t need to be capable of dealing damage to be a legal choice. (2004-10-04)
  • Can be used even when there is no damage to prevent. It prevents the next damage (if any) from the source this turn. (2004-10-04)