His condition was known at the time.
I have a copy of the World Book Encyclopedia from the time period that FDR was Governor of New York. He was not yet President. There is an article about him, with a picture (not in a wheelchair). The article says that he was disabled by polio and that he had leg braces and could not walk.
FDR did not make an ISSUE about being crippled, but before he was President, it was public knowledge, to the point of being published in a short article in an encyclopedia, that he was crippled.
Polio was a terrifying thing back then, with children dying and in iron lungs. People did not make GRAND, DRAMATIC emotional appeals from these tragedies then, as they do now, but everyone knew FDR had been partially paralyzed from polio, and everyone knew that he was still an indomitable figure, and this made them feel a little bit better, because polio seemed like such a death sentence, or a sentence to a life without hope, but there was FDR, governor of New York, crippled but powerful. And then there he was, President of the United States.
Nobody wanted to see him weak.
And he didn't want to be seen weak.
But everyone knew that he was crippled.
Even kids reading encyclpediae in the 1930s.
My bad. I should have said "widely known" or "common knowledge". But even those may have been inadequate qualifiers, based on your comments.
I have always been under the impression that FDR went to great lengths to hide his polio from the general public. Of course those close to him knew and those in the media knew. I did not mean to imply that those who knew was a very select group.