And there is a difference between collecting intelligence on foreign governments (which I don't think anyone could ever expect not to happen) and mass data collection. Part of the problem here is that spying on "terrorist" "suspects" is so broad and poorly defined that it could encompass nearly anything and becomes nothing but a convenient fig leaf for mass surveillance.

We lump too many things under the label of terrorism. Someone with the likes of a machete or a hand grenade is distinctly a law enforcement problem rather than a national security problem and cannot justify secret mass surveillance or data collection.

Once you take all of that out and get to the actual national security threats (i.e. nuclear or biological terrorism) you end up with a completely different threat model. More to the point, you need to keep a lot less secret because instances of attempted nuclear terrorism are much more rare. You don't have to classify every court opinion related to some idiot with defective instructions on how to make a pipe bomb just because you have to classify certain methods of preventing nuclear proliferation.

If you have to redact all the of the relevant facts, then any statement of the law is meaningless because it's unclear what sort of fact pattern it should be applied to. I realize this seems abstruse, but the fact pattern is very important in common law judgments. You can't just say 'the law is X' and have it be portable to any other case. The opinion would read something like: 'HELD: the government may xxxxxxx xxxxx when xxxxx xxxx xxx in a xxxxx and xxxxxx.' Read some judicial opinions in normal cases and then imagine how little sense they'd make if the facts were matters of national security and couldn't be published. For that matter it's quite hard for a lot of people to understand the law in many regular criminal cases where all the details are available.

Someone with the likes of a machete or a hand grenade is distinctly a law enforcement problem rather than a national security problem and cannot justify secret mass surveillance or data collection.

9/11 only involved boxcutters, but I'd say that it presented a rather significant national security problem when those turned out to be sufficient to hijack planes and fly them into high-value targets. There's an assumption in some corners that since we're now more aware of the risks, no hijacking can ever work again, but that's not the case.

You're also ignoring the fact that many kinds of low-level terrorist activity aren't open to direct investigation by law enforcement. For example, suppose you pick up signals about a plot involving Mr X, who has not yet arrived in the US but whose phone number you have managed to identify. If he's in a country that's friendly to the US you might be able to get their law enforcement people to investigate him, but if not then it's logical to monitor who he communicates with for prophylactic purposes.

You're basically assuming they would have to redact everything. Just replacing names and addresses with tokens that don't identify the specific subjects would get you most of the way there unless the specific fact pattern is unique to the suspect, and then you can redact what is necessary to make it less specific.

In addition to that, once any given investigation is over the opinions and redactions that were held secret for the purposes of that investigation should be published, and it shouldn't be so easy to keep things secret for decades just by making a facile claim of national security.

>9/11 only involved boxcutters, but I'd say that it presented a rather significant national security problem when those turned out to be sufficient to hijack planes and fly them into high-value targets.

9/11 was not a national security problem. 9/11 was a mass murder. It was shocking but we have inflicted more damage on ourselves in our overreaction to it than the terrorists did in committing it. More have died avenging the victims of 9/11 than died on 9/11.

A national security threat is a nuclear bomb, or a plague, or a foreign government infiltrating high level government offices in preparation for some kind of Communist takeover. Something that would be a factor of 1000 worse than 9/11 and present an actual threat to the security of the entire nation. This watering down of "national security threat" to mean any jerk who might kill some people with an IED is just a ruse to rationalize the use of extremist measures against everyone rather than taking into account the proportionality of the threat.

>You're also ignoring the fact that many kinds of low-level terrorist activity aren't open to direct investigation by law enforcement. For example, suppose you pick up signals about a plot involving Mr X, who has not yet arrived in the US but whose phone number you have managed to identify. If he's in a country that's friendly to the US you might be able to get their law enforcement people to investigate him, but if not then it's logical to monitor who he communicates with for prophylactic purposes.

So get a warrant and conduct surveillance on him then. That's not the same thing as spying and collecting data on everyone "for prophylactic purposes" at all.