[Natsu]

Slight correction regarding the part saying that 'anyone' may file one: "An amicus curiae brief may be filed only by an attorney admitted to practice before this Court as provided in Rule 5."

https://www.law.cornell.edu/rules/supct/rule_37

[schoen]

Sorry, that's quite right. I should have said "through an attorney" to avoid the possible interpretation that you could personally write and file a brief.

That rule is stricter than other Supreme Court rules related to filings by parties. If you're a natural person and not a corporation, you can file pro se pleadings before the Supreme Court in your own cases. Just not in other people's cases.

[Natsu]

Yes, that's how I interpreted it, but I thought I should point it out to avoid confusion. I also thought I remembered this being a fairly recent rules change, so there's that too.