What happened with previous way where countries (was it "Seven Eyes"?) would spy on each others citizens, as a way to workaround such "You shall not warantlessly mass-spy on your own citizens" limitations?
From the top of my head, I recall at least USA, UK, Australia and Netherlands were among those 7.
The countries involved in the 5 Eyes, 9 Eyes, and 14 Eyes alliances and their partners
Five Eyes countries: United States, United Kingdom, Canada, Australia, and New Zealand
Nine Eyes countries: The Five Eyes plus Netherlands, Norway, Denmark, and France
Fourteen Eyes countries: The Nine Eyes plus Italy, Germany, Belgium, Sweden, and Spain
Partners of the 14 Eyes: Israel, Japan, South Korea, Singapore, British Overseas Territories
From the top of my head, I recall at least USA, UK, Australia and Netherlands were among those 7.