Of course there are actual constitutional lawyers who also read these boards.
Sorry for the length, but it's shorter than some trip reports. Just consider it a trip report to the U.S. Supreme Court.
But first:
I'm not your lawyer, and this is not legal advice. I'm just giving you some general information about legal principles. If you have a question or a problem, get your own lawyer right away (who won't be me; I'm not taking new cases).
If you really want legal authority for governments' authority in a pandemic, it's pretty straightforward, but long. There are a couple of quick, layperson-friendly explanations of the law (I can't actually link these without getting moderated, so I'll explain how to find them on Google):
the American Bar Association has a page titled "Two centuries of law guide legal approach to modern pandemic" from April 2020;
on the other side of the ideological spectrum, the Pacific Legal Foundation has a page from April 2020 entitled "Are quarantine orders constitutional?"
I will try to explain the thinking behind these ideas. I am a U.S. Supreme Court practitioner (the 48th Supreme Court case I've been involved in was decided on July 1 this year, and I have been involved in drafting, defending and challenging sections of the Florida Constitution). Though this is not my area of expertise, my sense, based on a line of cases I've been watching since last year, is that the Supreme Court was very deferential to health authorities early on. But now, as the pandemic moves on, remedies and vaccines have appeared, and science begins to understand more and more, the Court is much more likely to impose the usual rules for reviewing urgent questions. It is no longer enough for a government official to say: "we fear this will happen." Now the burden of proof is going to require much more admissible evidence in a government showing that will support some restrictions on recognized rights. In other words, to impose a rule, the government will have to meet a standard of review that reflects the dangers at the time by presenting actual evidence rather than unsupported speculation. And isn't that what you think is the right way to go?
The best example of this trend may be last November's decision in
Roman Catholic Diocese of Brooklyn v. Cuomo, where the Supreme Court blocked New York's rules on attendance at churches and synagogues. The majority said:
“Members of this Court are not public health experts, and we should respect the judgment of those with special expertise and responsibility in this area. But even in a pandemic, the Constitution cannot be put away and forgotten.” And Justice Kavanaugh pointed out: “judicial deference in an emergency or a crisis does not mean wholesale judicial abdication, especially when important questions of religious discrimination, racial discrimination, free speech, or the like are raised.” Note: not just blah, blah, blah "I have rights," but specific assertions of traditionally-recognized, legally-enforceable rights. Courts, especially federal courts, don't issue "advisory opinions," only decisions about concrete, specific challenges to recognized rules and rights based on an evidentiary record.
To see how this works, look at three different cases, all involving Free Exercise challenges to pandemic rules: in May, 2020, in
South Bay United Pentecostal Church v. Newsom, the Court refused to block California’s rules that prohibited church attendance of more than 100 people. Last November, in
Diocese of Brooklyn, the Court blocked similar rules. Three days later, in
Spell v. Edwards, Justice Alito, a member of the majority in
Diocese of Brooklyn, denied a church’s request to block similar Louisiana rules, without even asking for opposing briefs. Why the difference? Timing and precision in the rules and the challenges.
The basic rule at play in
Diocese of Brooklyn is when “the challenged restrictions are not ‘neutral’ and of ‘general applicability,’ they must satisfy ‘strict scrutiny,’ and this means that they must be ‘narrowly tailored’ to serve a ‘compelling’ state interest.” These complex analyses apply differently at different times: early in a crisis, when information is scarce and the need for some action is urgent, the government gets more leeway than later in a crisis when much more is known and interim steps can provide some relief even if a final remedy is not yet available.
That is the difference between
Diocese of Brooklyn and other decisions that permitted governments to impose more sweeping restrictions. By now, the religious institutions challenging the rules have had months to comply with changing scientific and medical recommendations, and, according to the trial judge in that case (whose judgements are not easily deflected at that preliminary stage), have done an exemplary job. The Court simply told government officials that expectations of more careful and precise drafting and enforcement are growing ever stronger. The same evolution has occurred in recent cases involving protests and riots in American cities over the summer of 2020; earlier decisions gave more deference to law enforcement, while later decisions have been more nuanced in applying the First Amendment’s right of peaceable assembly.
How should that work here and today with masks and vaccines? The same way it would have last November. If the government wants to impose a particular rule that affects a known, strong constitutional right in how people get together (peaceably assemble), it has to meet "strict scrutiny" -- the highest and toughest legal standard of constitutional review. Not easy. The government must show, through specific evidence, that it has a "compelling" interest, which life and death usually are. But that's still a test that requires a showing. And after that, the government has to say that its remedy is narrowly-tailored to the compelling need. Again, difficult, and requires specific proof. Key question: will a court require the "least-restrictive alternative" remedy or just one that is "narrowly-tailored" to the circumstances? Up to the reviewing court, in light of the circumstances before it.
So will the government be able to impose new mask and vaccine requirements under this tough burden? Last November, we didn't have vaccines. Now we have many months and 164 million Americans' worth of vaccination history. That's a heavy evidentiary thumb on the scales. So the governments have a bit more work to do. But they're rapidly building the evidentiary record for it. And so far, the careful, measured responses reflect that governments learned their legal lessons last year, and know how to prepare their proof of why they need the measures they propose.
Will some governments mess this up? Of course. They're led by very fallible humans. But the legal rules are pretty straightforward, so both sides know what to do if they care to look.
But just saying "I have rights" doesn't cut it, even under strict scrutiny. Once governments meet their burden, those challenging the policy have a really tough time pushing a court into reversing a solid governmental plan.
You asked specifically about a vaccine mandate. Once there's an actual approval for use of vaccines (meaning they'll have at least 71,000 pages of documentation on effectiveness and safety, reviewed and approved by government experts), it'll be pretty hard to block a vaccine mandate if a government wants to impose it. That's why the Biden Administration is pushing to get full approval.