I think the point is that to do this, tax agencies around the world would have to cooperate with American tax agencies, which just creates another level of overseeing that has never happened before. It is another instance of Americans trying to force their wishes on the rest of the world.
Wouldn't a public company report how much tax it pays in different countries? Why would Ireland's tax authority have to cooperate with the IRS for this to work?
We have these things called "tax treaties" that have existed for decades.
Tax agencies around the world already cooperate with American tax agencies on matters similar to this. In fact, the proposal would actually reduce the amount of inter-agency cooperation required as it would great reduce the amount of treaty-related work the tax agencies have to carry out.
