Poll Position: What puts the Super in Superman?

I've long wondered what exactly it is that made Superman the mega-star he is when so many other characters from the Thirties long since faded away into utter obscurity (many of them found right here on these pages being made fun of, and what kind of life is that for a guy in tights?). Sure, he has lots of powers, but so did those other guys. And yes, he had a flashy costume, but so did a lot of the other crusaders running around the funny pages. Is it as simple as he was first, so he had dibs on the popular imagination?

Beyond that, though, the character has been through more re-imaginings and ret-cons and re-definitions than I can count, and yet his core still remains unquestionably "Superman". So what is it that makes him who he is, with a seeming death-grip on the American public consciousness as "the" super-hero? So here's the question I came up with to try and grapple with that issue:

{democracy:90}

  • Invulnerability: Doomsday aside, Superman pretty much sets the standard for invulnerability. I think in some ways this inability to be hurt is what drives him to want to be Clark Kent so badly; in a very real sense, pain and mortality are at the core of what it means to be human, and yet those are the very things Kal-el can never really experience while still being himself. Would a Superman who can be hurt like the rest of us still fly so blithely into danger? Charge so heedlessly to the front when action is required?
  • Super-strength: In terms of his power set, his strength has to be darn close to his invulnerability. The iconic images of Superman mostly involve him throwing cars or bending steel bars or smashing through walls. Yes, lots of other super-heroes are strong, but this is a guy who's relatively normal (if buff) looking, not a grotesque distortion of the human figure like The Thing or The Hulk.
  • Flight: Look! Up in the sky! The power of flight has absolutely fascinated humanity for thousands of years, and Superman's ability to float above us has got to be a key part of his charm. Sure, when he started out he was just a really good leaper, but flight came along pretty darn fast. Would a Superman who could only "leap tall buildings" instead of race over them still be Superman?
  • The Big Red "S": Maybe this is my graphic designer persona talking, but that logo is pretty damn iconic. It's instantly recognizable throughout the world, and its bright primary colors and bold design pretty much set the tone for the whole body of work. During the interminable "Reign of the Supermen" story arc, the replacements with a big bold "S" were simply more Superman than those without it. Branding is reality, folks, like it or not.
  • The Clark Kent identity: I think you can make a good case that Clark Kent represents everything Superman most longs for -- to fit in, to be a part of humanity, to be unremarkable, to be appreciated not for his powers but for his heart and mind and personality. We all want to be something we not, and you can argue that just as Superman is exactly that for most of us -- what we emphatically are NOT -- the fact that this very same model also most wants to be like us has a powerful attraction.
  • Code vs. Killing: Superman sets the gold standard for a purer, more traditional style of super-hero, and his code versus killing is pretty much the reason for that. The case is made explicity and brilliantly in "Kingdom Come", but a fundamental and deep respect for the sanctity of other life is core to who Superman is as a character. I don't think a murderous, rampaging, homicidal Kal-El is still Superman.

So there you have it. I usually chime in here with what I think the answer is for me, but I don't want to muddy the waters this time around, I'm too curious to hear what you all have to say. So make your case in the comments, and if you think I left out "the" answer, by all means lay out the smack-down!