[Huck]

His birth certificate says Barack. In high school and college he liked to be called Barry.

Oh, so the joke doesn't really work unless you say why did he change his name back to Barack or why does he now prefer to be called Barack.

[Lonesome in Massachussets]

The joke is fine as is. He used to call himself Barry, now he calls himself Barack. When I was in school there was an American born kid whose dad was from Pakistan. He preferred to be called Mo. (Actually, the Pakistani students were the most irreligious as a group, of any the nationalities. Persians were a close second.)