Every minister has witnessed people nod off in the middle of his sermon. Hey, it happens. The spirit is willing and all that . . .
But seasoned preachers know how to respond to those dozing off--there are ways to startle the sleeping beauty, perhaps even making them jump or twitch, thereby betraying the fact to others around them that they were sleeping during a sermon when they should have been paying attention.
Obama either didn't see Biden nodding off, or else his teleprompter doesn't have all the options that I have available to me.