Robert F. Kennedy stands in an open-top convertible and shakes hands with members of a crowd as he campaigns for the democratic Presidential nomination in Detroit, May 15, 1968. (Photo by Andrew Sacks/Getty Images)

Robert F. Kennedy stands in an open-top convertible and shakes hands with members of a crowd as he campaigns for the democratic Presidential nomination in Detroit, May 15, 1968. (Photo by Andrew Sacks/Getty Images)

Robert F. Kennedy stands in an open-top convertible and shakes hands with members of a crowd as he campaigns for the democratic Presidential nomination in Detroit, May 15, 1968. (Photo by Andrew Sacks/Getty Images)

Robert F. Kennedy stands in an open-top convertible and shakes hands with members of a crowd as he campaigns for the democratic Presidential nomination in Detroit, May 15, 1968. (Photo by Andrew Sacks/Getty Images)