That is a federal ballot, not a state office. The Constitution establishes the requirements for the Presidency. They do not include releasing tax returns, standing on one foot, or being an Episcopalian.
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.
Where does it say tax returns required to be president?
They could require that electors provide their tax returns, they cannot demand the President present his tax returns…no more than they can demand that electors only vote for someone who is at least 40.
Read it again.
again
The ONLY requirments to be eligible to be on the ballot:
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.