A character’s race matters when it matters, and though that seems like a tautology because it is, let me explain what I’m talking about.

Marvel’s annoyed everyone with the casting of Tilda Swinton (the whitest woman alive) to play a character that had throughout his fifty-year history always been depicted as an Asian guy. It helped not at all when the screenwriter poked his head out of his hutch to offer truly foolish excuses about not wanting to offend China, and flailing out at “SJWs”. (I cannot stress this enough: never say SJW. It instantly turns you into a PTI (Person To Ignore).)

People have declared this Whitewashing, and many hashtags have been flung at the offense; one of them was interesting and caused this little screed. It was #johnchoas or #starringjohncho or #chomygod or something like that, and it Photoshopped John Cho into starring roles in Hollywood blockbusters.

Most of the films and roles were ones that John Cho would have been perfect for: he’s charismatic and handsome and funny and a movie star. Throw him in the gym for six months and teach him how to shoot and he can be Jason Bourne. He could have played any of the leads that go to Chris Pine or Ashton Kutcher in those formulaic romcoms, instead of the best friend.

But there is also an Avengers poster with him ‘shopped in as Captain America, and that part he could not play; this brings me to my point about casting (and obviously this is just for fictional characters being translated onto the screen. If you’re doing an experimental play, then cast who ever you want): in regards to the race and gender of a character, you need to ask whether these qualities are intrinsic in nature, or arbitrary.

Let’s take my favorite hero, Spider-Man. Since his first appearance in 1962, he’s been depicted as a white guy, and portrayed by white guys in the movies. Is this necessary? I would argue not: not a bit of Spidey’s character has anything to do with his race. Peter Parker is a lower-middle class kid from Forest Hills, Queens, with a brilliant scientific mind and the most powerful sense of humor in the Marvel Universe. He has an Aunt May, and he’s a photographer, and he likes redheads. Neither race nor gender inform his characterization.

The same could be said for most of the dopey white guys punching each other on the screen nowadays: you could make Tony Stark into Toni Stark and cast Aisha Tyler in the role (because Aisha Tyler should be cast in every role) and not have to change any of the dialogue. Bruce Banner is white, but he doesn’t have to be.

Certain characters, however, require actors of a certain ethnicity. Black Panther has to be black. Conversely, Black Widow has to be white. The Kingpin can be any color you want as long as he’s enormous; Daredevil has to be Irish-Catholic, or he’s not Daredevil anymore, just a blind guy doing karate in an alley. Luke Cage is a black guy, but Iron Fist (Jesus, that name) only needs to be a rich American kid.

Captain America has to be white, though, at least the Steve Rogers version: the U.S. Army–still a few years away from being desegregated by Truman–would not have picked anyone but a white boy to be their Super-Soldier. Nazism could only be fought with the blondest, blue-eyedest guy that Tommy Lee Jones could find.

(There was a comic called Truth a while ago that asked a good question: wouldn’t the Army have tested the Super-Soldier formula? And who do you think they would have tested it on?)

My vote for best color-blind superhero casting would be Denzel Washington as Batman, and as long as we’re in the realm of imagination: I’d cast Denzel twice. First, we use the Time Sheath to go back and get Denzel in his 30’s and have him be Action Batman and slap muggers around and stand on top of the Batmobile yelling at people. THEN, we get present-day Denzel and do Crazy Batman, where he’s old and broken and been driven insane by Gotham City, and ambles through town in broad daylight wearing Batarmor and firing wrist-rockets at pickpockets.