After reading some of his speeches, I see one rhetorical device used over and over by Obama, some examples for it include:
- large or small
- wealthy or poor
- able or disabled
- gay or straight
- young or old
What is it called? Is it a simple antithesis?
I think juxtaposition is the name of this literary device.
“It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness." Charles Dickens
The technical term is merism, the literary device of referring to a thing by enumerating some or all of its constituents.
A particular form of merism, which employs two polar terms to designate a totality, is frequently employed in the Hebrew Bible. Think for instance of the Tree of knowledge of good and evil, where knowledge of good and evil is understood by Hebrew scholars to mean not the ability to distinguish good from evil but the knowledge of all things.
It is frequently remarked that Obama's rhetoric owes a great deal to the pulpit style of African-American preachers, and I think it is no great stretch to see his fondness for this device as similarly founded.