No, it is not a formal legal requirement for the President of the United States to be married to an American citizen. The United States Constitution lays out the eligibility requirements for someone to become President in Article II, Section 1, Clause 5.
According to the Constitution, to be eligible for the presidency, a person must meet the following criteria:
- Be a natural-born citizen of the United States.
- Be at least 35 years old.
- Have been a resident of the United States for at least 14 years.
There is no specific mention of marital status or any requirement that the President's spouse must be an American citizen. As long as a person meets the above three criteria, they can run for and become President regardless of their marital status or their spouse's citizenship.
Throughout U.S. history, there have been unmarried Presidents, Presidents who were widowed during their term, and Presidents with foreign-born spouses. The eligibility criteria primarily focus on the candidate's individual qualifications and citizenship rather than their marital status or their spouse's citizenship.