Every time there is a Presidential election in the USA, trees are felled and converted to communicate tedious and ultimately almost irrelevant discussions as people seek the answer to one question: is the candidate qualified to be POTUS?
On one level, the question is pretty much unanswerable. There is only one job of POTUS. There is no apprenticeship for the job. Vice-President is a ceremonial role, usually occupied by a person deemed to be no threat to the POTUS.
Running a country is NOT the same as running a business. Anybody who claims that it is should be asked to explain how it is the same. Answers like “balancing the checkbook” will instantly show the person to be unserious.
So, a lot of viewpoints about qualifications boil down to intangibles, like the horrible question about whether somebody “looks Presidential”. This implies that being POTUS is all about artifice and posing, not achivements, a triumph of style over substance.
On one level, however, it has never been easier to examine a person’s qualification to be POTUS. The internet can be a good source of information as long as the information is verified.
In the case of Ben Carson, a well-known pediatric surgeon, one interesting viewpoint on his qualifications is that of fellow medical practitioners. The view is not flattering.