He's Trump's idol - the new President took his 2016 slogan 'Make America Great Again' straight from Ronald Reagan's barnstorming 1980 campaign. But like Trump, Reagan had a long past in entertainment - and one that might have scuppered his political career before it really took off. For BBC World News, historian Adam Smith tells the extraordinary story of Reagan's last movie. In The Killers (1964), Reagan played a criminal for the first time, and portrayed California businessmen as corrupt and violent - just months before real California businessmen launched him into national politics. But why did he do it? And what might have happened if The Killers had been shown on TV as planned?