"Calling one's bluff" doesn't imply that there was a bluff in the first place. It's a common figure of speech. https://www.vocabulary.com/dictionary/call%20on

"Calling one's bluff" doesn't imply that there was a bluff in the first place. It's a common figure of speech. https://www.vocabulary.com/dictionary/call%20one%27s%20bluff https://www.vocabulary.com/dictionary/call%20one%27s%20bluff If I say "I demand X or else I resign", (I don't know if that was actually said) I think it's fair to consider that a conditional resignation.