From the BBC comes an assessment of the original and real American Superman.

“…it blew my mind when I saw it. He’s essentially a violent socialist.” The earliest issues of Action Comics bear out this assessment. When there are wrongs to be righted, Superman knocks down doors and dangles suspects from fifth-storey windows, and he makes hearty jokes while he’s doing so: “See how easily I crush your watch in my palm? I’ll give your neck the same treatment!”

…of the people who are roughed up by this boisterous outlaw…the majority are so wealthy that they don’t need to rob banks: there is the mine owner who skimps on safety measures, the construction magnate who sabotages a competitor’s buildings, the politician who buys a newspaper in order to turn it into a propaganda sheet. Rather than being a typical costumed crime-fighter, then, the Superman of 1938 was a left-wing revolutionary.

The S was for being an American socialist, a super one at that.