The myth of the businessman-president:

Well, there goes Teddy Roosevelt, the writer, rancher and police commissioner, not to mention his distant cousin Franklin Roosevelt, the assistant naval secretary and politician, or Dwight Eisenhower, the career soldier. Ike’s résumé, which includes defeating the world’s most concentrated form of evil in Nazi Germany, would not be not enough to qualify him for the presidency...history shows that time in the money trade is more often than not a prelude to a disastrous presidency. The less experience in business, the better the president.


http://opinionator.blogs.nytimes.com/2012/05/31/the-wrong-resume/