You know that feeling when you're talking to someone and their eyes kind of glaze over? Maybe they even stifle a yawn? Yeah. Political speaking is about keeping people engaged. Get too far afield, and the audience will change the channel to Futurama reruns or, worse, vote for your opponent.

One great way to keep people from totally zoning out on you: inject a little rhythm. If an inaugural address is like a song, then parallel structure is kind of like a verbal back beat. And repeating syntax and phrases are like catchy riffs that keep the song going.

For the best example of Obama's use of parallel structure, reread part of paragraph 7:

On this day, we gather because we have chosen hope over fear, unity of purpose over conflict and discord. On this day, we come to proclaim an end to the petty grievances and false promises, the recriminations and worn-out dogmas that for far too long have strangled our politics. (7.1-2)

Just about everything in these sentences qualifies as parallel structure. See how that kind of poetic repetition is working for him? He repeats "on this day" and balances long sentences with mirroring syntax ("hope over fear, unity of purpose over conflict"). Finally, the repeating "the" also qualifies ("the petty grievances," "the recriminations"). There's so much repetition in here that if we were Obama, we'd probably have had to plan out every time we'd take a breath.