IIRC customarily a former president of the United States of America is still addressed as, “Mr. President.” In written form such as a news article I think it would be “former-president Clinton” or “former-president George H. W. Bush” if you need to distinguish between two presidents with the same last name, and subsequent references would be to “Mr. Clinton” or “Mr. Bush” as long as there’s no ambiguity, but I would defer to whatever style guide applies to your writing. I’m pretty sure that’s covered in the AP Stylebook and that’s as good an authority as any for US English. I have an old copy somewhere but it’s not easily accessible right now.
IIRC customarily a former president of the United States of America is still addressed as, “Mr. President.” In written form such as a news article I think it would be “former-president Clinton” or “former-president George H. W. Bush” if you need to distinguish between two presidents with the same last name, and subsequent references would be to “Mr. Clinton” or “Mr. Bush” as long as there’s no ambiguity, but I would defer to whatever style guide applies to your writing. I’m pretty sure that’s covered in the AP Stylebook and that’s as good an authority as any for US English. I have an old copy somewhere but it’s not easily accessible right now.