Anaphora is like parallel structure, but more specific. When Obama uses the same word at the beginning of multiple sentences in a row, he's doing the Anaphora. Which sounds like a super nerdy dance—which, tbh, we'd kind of like to learn.

Anaphora helps the audience keep track of items in a list and, if used correctly, it can even add literary and/or Biblical undertones to a speech.

Check out paragraph 5 of the speech, where Obama repeats the word "our" to describe the state of the country:

Our nation is at war against a far-reaching network of violence and hatred. Our economy is badly weakened, a consequence of greed and irresponsibility on the part of some, but also our collective failure to make hard choices and prepare the nation for a new age. Homes have been lost, jobs shed, businesses shuttered. Our health care is too costly, our schools fail too many—and each day brings further evidence that the ways we use energy strengthen our adversaries and threaten our planet. (5.2-5)

This is an example of effective anaphora because the sentences are long and compounded—so the speech doesn't sound too repetitive. Sneaky, huh? At the same time, the repeating structure is an effective way of creating a grocery list of America's political issues. Unfortunately, you can't pick up a family-size pack of global warming solutions at Costco.