The laughter went flat. The smiles froze before they had time to disappear. In the back of the Ambassador Hotel ballroom, David Steiner couldn't tell what was happening. But a change in mood raced through the crowd like an electrical charge, arcing from face to face.

Sen. Robert F. Kennedy had just finished his victory speech after winning the California primary and exited through a door near the podium. It was just after midnight on June 5, 1968.

At 25, Steiner, who left his job at the Justice Department to join the campaign, had never before felt so giddy with purpose.

Now an awful energy emerged from the closed door. He felt a rush of dread.

Steiner ran toward the door and found himself suddenly smashed against it in the pandemonium. Women in straw boater hats cried. Men covered their mouths in shock. Steiner tried to pry the door open. But the crowd pushed against him. He saw one woman go under, another shoved hard against the wall.