This is impossible. One of the problems with the blatant misuse of forecasting is governments using it it to compare outrageous black swan futures against real history. It leads to claiming that "spying on everyone 24/7 to prevent an infinite number of terror attacks" is in everyones interest. The reality is that a limited number of black-swan terror attacks is actually a minimal cost compared to destroying social fabric modern western society is built on.

This type of false thinking is what allows government officials to manipulate public thought into agreeing to give up their rights. This has literally led to the FBI radicalizing young men in order to 'catch them' in the act -- thus justifying their existence by creating the very black-swan event they are supposed to stop.

For now it seems that terrorist attacks made more impact on social fabric than US or French surveillance.

Well, they did enable government to implement those surveillance programs. It was already in the works, but terrorism is a wonderful pretext (along with paedophilia, Nazism, and starving authors).

Measuring how much something did not happen looks pretty tough. I have a lucky rabbit's foot, and I have not been attacked by a bear. How many bear attacks has my lucky rabbit's foot prevented? Seven? A million?

Either an informed electorate runs the country or the security services do. That sounds like a false dichotomy, but if all of the important information is classified, and voters are prevented from becoming informed (which is what the security services want)? I don't see how the system can continue to operate.

And that doesn't begin to address the catastrophic civil liberties problems the surveillance state brings. I'm just wondering who is in charge.

When developing complex and robust systems, the measure of effectiveness of a program is how little the original system changes in response to new stimulus. If the system constantly needs to change, it's not meeting the stating requirements.

Unless of course the program contributes to causing those attacks in the first place. Now? Probably not. 20 years time? Perhaps.

Soo... which were prevented? These must somehow end up as court cases eventually, right?

Didn't think so.

Those cases are handled in "secret courts" run by "secret judges" with "secret prosecutors".

Apparently the defense counsel is also secret since they don't come out afterwards to say what happened to their clients. Assuming the prosecuted had defense counsel.