Nixon uses a lot of rhetorical questions in this speech.

A lot.

Way more than can be listed here conveniently.

Yeah…just go read it.

These questions pepper the speech, acting as transitions to topics Nixon wants to address. Mostly they're softball questions Nixon poses to himself, making it appear as if he has all the answers and there's nothing more to explore. The technique's a powerful one, especially when combined with his emotional presentation.

Check out this one, for instance:

Let me say, incidentally, that some of you may say, "Well, that is all right, Senator, that is your explanation, but have you got any proof?" And I would like to tell you this evening that just an hour ago we received an independent audit of this entire fund. (61-62)

Rhetorical questions are one of those tools of rhetoric that's older than dirt. Still, even for a guy like Nixon with little formal training in public speaking, you don't fix what ain't broke.