No one is giving the real answer to this question which is that these laws touch on the legality of capabilities the US does not want to acknowledge it has, and so it won't. Secret information in the US is like glitter - if you touch it, it spreads to you too.
It's not just "here's this law about spying in the abstract," which can be talked about in the open; it's "we're using the MIND READER 5000 under Title XVII powers delegated by the President to the Mind Reading Organization to conduct mind reading on persons X, Y, and Z." The legal briefings and rulings on the facts will by necessity reveal the nature of the technology or technique in question, and so, they are classified. If I recall correctly it was a big deal for the ACLU to get a lawyer a security clearance so they could interact with these courts, but I could be misremembering.
It's not just "here's this law about spying in the abstract," which can be talked about in the open; it's "we're using the MIND READER 5000 under Title XVII powers delegated by the President to the Mind Reading Organization to conduct mind reading on persons X, Y, and Z." The legal briefings and rulings on the facts will by necessity reveal the nature of the technology or technique in question, and so, they are classified. If I recall correctly it was a big deal for the ACLU to get a lawyer a security clearance so they could interact with these courts, but I could be misremembering.