What power? The US gave up power by not signing. The treaty is standardizing the process for sharing cybercrime evidence and prosecuting individuals. It has signatories pledging to align their laws and create new ones to make the same cybercrime illegal.
This isn't giving any country any sole power over cybercrime prosecution decisions.
Signing on to bad treaties is bad. Treaties can both restrict what you can do and compel you to do things that you don't want to.
For example: "Compelled Technical Assistance: The draft requires countries to adopt laws enabling authorities to compel anyone with knowledge of a particular computer system to provide *necessary information* to facilitate access."
The US would have to have laws that would force you to provide login information to systems if the government wanted access to it. This would run contrary to the 5th amendment.
https://www.eff.org/deeplinks/2024/07/effs-concerns-about-un...
And what's that thing about treaties and the Constitution?
SC has already ruled that when treaties and the constitution conflict, the latter is supreme.
Has SCOTUS ever later revisited and reversed a previous decision?