Some argue that "Ben Carson is not ready for primetime":
"Most presidential candidates enter the race without fully formed and well-reasoned opinions on foreign policy. That’s true, and there is time for Carson to make up his knowledge deficit. But there are several candidates with a fuller resumes who are simply more experienced at the business of politics than Carson. These able candidates would not clutter the news cycle with avoidable gaffes that compel conservative to come to their defense. Dr. Ben Carson is simply not ready to run for the presidency"
UPDATE: He's in- Ben Carson Officially Announces a run for President in 2016