The company that produced the payload for the rocket is in the US and was denied their application to launch this payload because it poses a risk to other satellites and spacecraft.
If all companies were outside of the US then it would come down to whether a treaty or similar agreement exists (of which I am not aware).
Specifically, under the terms of the Space Liability Convention, a state which launches an object into space is liable for damages caused by that object. A practical example was the crash of Kosmos 954 over northern Canada: https://en.wikipedia.org/wiki/Kosmos_954
If all companies were outside of the US then it would come down to whether a treaty or similar agreement exists (of which I am not aware).