Article II, Clause 5.
Obama’s loyalty is divided between nations.
I assume you mean, "No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty five Years, and been fourteen Years a Resident within the United States."
Says nothing about dual citizenship OR divided loyalty.
Nothing.
Zero, zip, zilch, nada.
Perhaps you are seeing penumbras and emanations?