[jandrewrogers]

The Federal government has severely circumscribed authority to restrict travel, as the Supreme Court has repeatedly determined it to be a fundamental Constitutional right on the same level as freedom of speech. You can’t suspend that right without narrowly tailored due process for each of 330 million Americans. (This cuts both ways — there are several things that are effectively impossible because “due process” doesn’t scale regardless of the purpose.) This is the reason no State implemented real “lockdowns”, the Supreme Court has overturned such attempts many times historically, it is settled law at this point. States actually have fewer restrictions than the Federal government in this regard.

Similarly, effective contact tracing by the government is illegal in the US, ignoring that the disease was endemic before anyone even noticed. It isn’t just illegal, the US infrastructure is intentionally designed to make it extremely difficult to do at a technical implementation level, with the idea that it would hinder potential abuses. You could modify the systems to make contact tracing work, ignoring legality, but it would require at least a year of lead time to do the technical implementation. Many senior people in US government did ask about this early in the year and were repeatedly told that implementation would require a very long time both legally and technically. So they dropped the idea.

No amount of “real national commitment” will address these issues, and denying that these limitations exist isn’t the basis for a constructive policy.

[slg]

You are speaking as if you have indisputable facts on your side which doesn't appear to be the case. The Federal government has broad power to respond to communicable diseases and the full extent of those powers can only really be known as new court cases are decided.

There are also steps between what we did and the type of martial law style lockdowns and quarantining done in places like China. You don't need 100% participation in lockdowns or coverage for contact tracing to get the R0 below 1 which will lead to dropping case numbers.

[jandrewrogers]

These are indisputable facts, there is a lot of case law on the limits of travel restrictions in many contexts. They can’t even use regulatory powers to implement de facto restrictions on travel by common conveyance (e.g. closing all the roads or prohibiting the sale of gasoline) — that has already been decided broadly by the Supreme Court in multiple cases.

Restrictions on freedom of travel, as laid down by the Supreme Court, are similar as for freedom of speech: the state must have a reasonable belief and compelling interest that a specific individual is an imminent threat to other people. You can’t quarantine a broad class of people over wide geographies on vague grounds, it requires clearing evidentiary hurdles that a narrowly targeted group of people harbors the disease. As a concrete example, this is the legal basis for how people remove their names from the No Fly List; having terrorist sympathies does not make one an imminent threat, and so the right to travel by common conveyance is upheld. (Unfortunately, the government has been successful at removing standing from everyone that challenges the Constitutionality of the No Fly List, but USSC justices have already made public statements that they take a very dim view of the legality of the practice.)

And this is why there were no real lockdowns. The AG in every State is well-aware that broad prohibitions on travel aren’t Constitutional and would lead to an instant court injunction. It has been tried in the past on many occasions. The most they can do is strongly disincentivize travel using their regulatory power over public establishments i.e. give people no reason to leave their house.

[pbourke]

> t isn’t just illegal, the US infrastructure is intentionally designed to make it extremely difficult to do at a technical implementation level, with the idea that it would hinder potential abuses

You think that the country which went from never leaving the earth to landing on the moon in 8 years, from 0 to hundreds of planes and dozens of ships per month in a few short months (WW2) couldn’t stand up a national infrastructure for contact tracing? Don’t confuse lack of will with lack of capability.

[jandrewrogers]

This challenge isn’t just legal and operational, the required computer science and data infrastructure software literally doesn’t exist. I am a subject matter expert on this and was consulted by a few national governments to see if it was feasible. Large-scale technical experiments were run in the US several years ago.

If you use off-the-shelf computer science, you have an O(n^2) problem on a data model that is growing by several petabytes per day. Existing systems can’t even ingest data at that rate in a useful way, never mind analyze it. Much more scalable algorithms exist; this was literally the topic of my supercomputing research back in the day. If you can severely constrain the data model in certain ways that are not possible in many countries, or you have a small enough population, you can kinda sorta brute force it. In practice no one is AFAIK, because off-the-shelf software simply isn’t designed for it, even at small scales. The US has an unconstrained data model combined with extremely high scale and topological complexity. You can’t magick state-of-the-art exotic data infrastructure into existence.

I did “what would it take” studies earlier this year for a couple governments. We are talking about 100k lines of advanced C++ for a system design that has never been built before, only theorized. It isn’t something you do over the weekend. Even in the most optimistic scenario, building the software would take at least 18 months. For COVID, there is no point (but they are still interested for the next pandemic).

We know from prior experiments that if a disease is endemic in a population and extremely draconian lockdown measures are not realistically possible — both true in the US and some parts of Europe — then contact tracing is basically an exercise in futility unless you have some exceptionally advanced data infrastructure (we don’t) and the legal authority to use it (the US doesn’t nor many countries in Europe).

Don’t confuse the lack of capability with a lack of will. The fact is that I was approached by multiple national governments on this subject very early on because they know I design this type of data infrastructure.

[kaba0]

Not who you are responding to, but really interesting comment, thanks!

I am not too knowledgeable on the topic, may I ask you what sort of confidence is required for a well working contact tracing application? A naiv those-who-live-together is so utterly useless that it was rejected? And do I get it right, you meant to real-time track everyone and if someone turns out to be infected, everyone gets quarantined who they met in the preceding days? What percentage of contacts can “slip through” so that it is still effective? Isn’t there a working trade-off like counting people who work together and family or is it still subject to unimplementable exponential explosion?

Or am I asking the wrong questions as these are epidemiologic ones rather than technical? If so, excuse my lack of knowledge on the topic.

[pbourke]

I’m not sure what you’re talking about. China did this in a few weeks. I’m not even talking about automated tracing of cell phone signals - just databases and people making phone calls.