Will Trump's trial appearances be the death of his campaign? 16:48

Buckle up folks, because we’re in uncharted territory. Today, On Deadline is diving into a first of its kind spectacle as Donald Trump becomes the first president ever, former or sitting, to appear as the defendant in a criminal trial. Opening arguments began Monday in the "hush money" case in New York City that’s expected to last about six weeks. Here's how things started. 'On Deadline' is hosted and produced by Lauren Barry. It's also produced by Joe Hiti, Christy Strawser and Myron Kaplan. Sound design by Joe Hiti.