Leave it to the Brits! There's Mitt! He was a Mormon missionary at the time so was exempt from the draft. The photo was taken at Stanford University. Mitt was 19.
His sign says "Speak Out, Don't Sit In." He was taking an unpopular student stance at the time, and he was hardly a hippie. He was protesting the protest. Students were taking over the President's office due to an unpopular test designed to help authorities decide who was elligible for the draft.
According to the article, Mitt even told another student that he would handle the press, since he had some experience with them.
His father was, of course, in politics.