IANAL, but I think given Lavabit's experience it's best to get a lawyer before saying screw it. The ACLU and EFF are probably at the forefront of expertise and curiosity when it comes to NSLs.
https://www.aclu.org/national-security-letters
I mean honestly what's so difficult about "Congress shall make no law"? We're not talking about someone yelling "fire" in a theater. NSLs are facts, the searches they authorize are facts, and the gag is also a fact. And it's also not like this even remotely resembles treason or sedition.
Disagree with the restriction on free speech on its actual merits, not by saying "there's very few restrictions on free speech" when in fact this is not the case.
The "yelling fire" case was about a Jewish anti-war socialist who distributed pamphlets urging men to resist the WWI draft as a violation of the 13th amendment.
The idea that a National Security Letter can serve as a secret warrant against a 21st century Charles Schenck like Edward Snowden is interesting.
Neither falsely claimed there's a fire; they are/were men speaking out against war and unconstitutional acts. Anti-war speech should be especially protected.
Publishing a NSL is a defensive act against an immoral and oppressive government. The idea that they are using the NSLs to suppress freedom of speech and fight advocates of freedom of speech should only embolden the opposition.
I mean honestly what's so difficult about "Congress shall make no law"? We're not talking about someone yelling "fire" in a theater. NSLs are facts, the searches they authorize are facts, and the gag is also a fact. And it's also not like this even remotely resembles treason or sedition.