Most likely, I know it seemed like most people watching the speech in the off-topic thread were hearing it for the first time. At one point there was an entire page of reactions to that one line
He'd used it before? I hadn't heard it before, and I mean I follow politics but I don't have time to watch every speech Obama gives, so that larger profile events like this are what the majority of the country sees as some of their only exposure to politics is not surprising in the least.