Today 's top presidential candidates weigh in on what makes a president great . John McCain : FDR was the greatest president of the 20th century . H.W . Brands : America is not ready for another great president right now . Joan Hoff : Wartime presidents tend to be considered great , but perhaps no longer .
America 's top presidential scholars weigh in on what makes a president great . Richard Reeves : FDR was the greatest president of the 20th century . H.W . Brands : America is not ready for another great president right now . Joan Hoff : Wartime presidents tend to be considered great , but perhaps no longer .