When addressing a former President of the United States in a formal setting, the correct form is “Mr. LastName.” (“President LastName” or “Mr. President” are terms reserved for the current head of state.) This is true for other ex-officials, as well. When talking about the person to a third party, on the other hand, it’s appropriate to say, “former President LastName.”
That’s the formal one we’ll see in the news media most of the time. IRL, it’s just last names. “Is Obama still podcasting?” “What’s going on with Trump’s trials”. “Biden’s dog bit another person”.
Emily Post etiquette resource
That’s the formal one we’ll see in the news media most of the time. IRL, it’s just last names. “Is Obama still podcasting?” “What’s going on with Trump’s trials”. “Biden’s dog bit another person”.