>>It's a sticky situation, but all things should be negotiable when it comes to state-state.
>
>What if it's not [negotiable]?.....

But that's something that has to be EXPERIENCED, not assumed. Especially after the WMD debacle.
When talk after talk after talk after talk after talk... have happened and there seems no resolution, then the "traditional" countermeasure of blockade, boycott, blacklist and belittle comes next.
*IF* that should result in some injury (i.e. attack) on one/some of the blockaders BY the blockaded, then measures like bombing can be contemplated.