My words literally betray me.
I am guessing you cannot play a card to your tableau or change the rules if neither lead you to be winning?
In that case you don't play a card at all and just fold? Or do you play something and then determine you lose.
You can play a card to your tableau and not be winning.
You cannot play a card to change the rules if you aren't immediately winning though.
This only ends up mattering when you are playing a 3 hoping to draw a card that you could play as a rule.