An officer sees Clark looking around a crime scene and says
Move along, (You shouldn't be here?) sir. This is a crime scene.
No, just "keep on going." It's what cops are thought to always say at crime scenes. I've seen the phrase used metaphorically in political discussions to imply that the media is ignoring some misdeed of a political leader.
"Don't worry, the president just suspended habeus corpus, that's all. Move along! Nothing to see here!"
Thanks, Delmobile!