Remember how a secrecy jurisdiction is defined. Secrecy jurisdictions are places that intentionally create regulation for the primary benefit and use of those not resident in their geographical domain. That regulation is designed to undermine the legislation or regulation of another jurisdiction. To facilitate its use secrecy jurisdictions also create a deliberate, legally backed veil of secrecy that ensures that those from outside the jurisdiction making use of its regulation cannot be identified to be doing so.
The impact of all tax haven activity is extra-territorial.
The impact of all tax competition is also extra-territorial.
If it is now illegal for a tax to have an extra-territorial impact the impact is enormous. It is of minor consequence for the FTT, where a few tweaks would solve the problem, but the impact on tax havens and tax competition would be wholly beneficial. Be careful for what you’d ask is what I’d say to those trying to use competition principles to beat the FTT: this could rebound on you, very strongly.
There’s a difference between actively taxing someone in another jurisdiction and passively allowing someone not to be taxed in another jurisdiction.
I am guilty of murder if I murder someone. I am not guilty of murder if I’ve nothing to do with the fact that a bloke 50 miles away glasses someone’s jugular.
France attempting to tax American banks trading French bonds in London is extra-territorial taxation. The UK not taxing Americans trading French bonds in London is not.