Does a president running for reelection have to be nominated?

Yes, a president running for reelection must be nominated by their political party to appear on the ballot. This nomination typically occurs during the party's primary elections and national convention. However, if the president is running as an incumbent, they often face less competition for the nomination compared to challengers. Ultimately, the nomination process varies by party and can also include independent or third-party candidates if they choose to run.