"This will cause unimaginable disaster! You can't imagine how bad it will be!"
No, even if it did happen, it will cause a completely imaginable disaster, and we can start going through the consequences now. I can imagine it just fine, thanks, even if it doesn't make me happy.

"If we don't do this the enemy have already won!"
Let's first check out what the enemy objectives might be, and compare that with the effects of your proposed action, shall we? They should not match.