Then you presumably agree with the 20th Amendment that a President-elect who has “failed to qualify” by Jan 20th cannot **ACT** as President. Right?
The oath of office has nothing to do with when the person becomes President - only with when they can begin to ACT as President. They can never ACT as President if they fail to take the oath and/or they fail to qualify.
Now, what are all the qualifications to be President that are mentioned in the Constitution?
1. He presented his evidence that he is a natural born U.S Citizen.
2. This was deemed sufficient and qualified and placed on the ballot by 50 Secretary of States.
3. He won the General Election and the Collegiate cast their vote for him.
4. The election was certified by the specific governing authority specified in the U.S Constitution. The process is negative affirmation.
5. Not only did he do this once in 2008, but he did it again in 2012.
So, you’re confusing the fact that you don’t like him and that he sucks as a President with him [Obama] being ineligible.