There aren't really any groups that want full control that have any power really - it's more like systemic pressure.

A police investigator trying to do his job is 100% sure he can solve crimes this way, to him, there is zero doubt about the benefit of being able to get info from social media, it's a moral concern.

The anti-terrorist squad - same. They see all sorts of threats, daily they are truly concerned, they're all waiting for horrible things to happen and in each case they 'knew they could have prevented it'.

Then you get corporate interests, who just want to 'sell gear to make money'

Maybe it even works really well ... because of 'checks and balances'.

But then, the 'checks and balances' start to fail, either from corruption, bad legislation, legal rulings etc.

Those forces all collide into the 'slippery slope'