Re that strange absence of memorable phrases: it's not just balanced by one strength, it's book-ended between two: conceptual complexity/coherence on the macro side, and cadence on the sub-micro. At least in 2007/2008, less so now, Obama's speeches were musical, hinging on repeat phrases (yes we can) and on the simplest of rhetorical devices, various forms of parallel structure, e.g. anaphora, the repetition of beginning words (also a lot of parallel phrasings in series -- "A man touched down on the moon, a wall came down in Berlin" etc.). It was no accident that Will.i.am was able to set one of his speeches to music to some effect.I heard this kind of music in Obama's eulogy for Mandela. It was a speech of strong cadences that gave shape to the speaker's thought. At his best, Obama is a prose poet, and today he was Mandela's poet.
Poet, not novelist. At the outset, Obama set himself a problem: