There are three requirements in the US Constitution to serve as President of the United States:
1. You must be at least 35 years old.
2. You must have been a resident within the United States for at least 14 years.
3. You must be a natural born citizen.
That’s it. There is NO REQUIREMENT that you must have made your tax returns public.
President Trump has the same rights as every other US citizen. He has the same right to the presumption of innocence, to due process, to privacy and to the protection of his tax records by the IRS that every other citizen has. He has neither any legal requirement, nor any constitutional requirement to make his tax returns public any more than any other citizen has.
The American people already spoke on this issue. They elected President Trump knowing that he did not make his tax returns public. The decision to show or not show your tax returns is a political decision and the people elected President Trump without that.
No one is above the law. But neither are they beneath the law. President Trump is entitled to the same legal privacy of his tax returns as every other citizen. He has no requirement to release them. That decision is entirely his and no one else’s.