Yes. They've very clearly stated that sanctions would lead to war. If they back down here, they will take a huge blow to their credibility and respect. (I know, I know, 'what credibility and respect?', you're saying).
If they're unable or unwilling to back up their threats, then we can tighten the noose. If they try and back it up, they'll be leaping into a fight that they are sure to lose, and lose badly.