If a crisis card has the option to discard a number of cards and the player or players can't discard as many cards as reqired do you have to take the other option on the card. I don't have the game in front of me so I can't give a specific example from the game, but it did come up in our first game.

From the rulesbook page 30:

Choice Crises: When a player makes a choice on a Crisis
Card, he can always choose the top or bottom section of
the card, regardless of whether he will be able to fulfill the
game text listed (unless the card specifically restricts this).

So you can pick the discard option even if you don't have cards to discard.

Thanks, I missed that in the rules.