The subpoena is a command to the possessor of the data, which tells the possessor of the data to produce it, with a particular deadline. Since this deadline is in the future, the subpoena can be challenged legally (normally by requesting a court to "quash" it; more riskily, sometimes by complying imperfectly or not at all, and then arguing in response to an attempt to punish the noncompliance that this was reasonable). A subpoena can be issued by many entities, for example including some law enforcement entities themselves, or a lawyer actively involved in litigation. (Yes, lawyers can personally write and issue subpoenas.) The subpoena is, however, enforced by a court, in the sense that the court is asked to punish people who fail to obey it.
The warrant is a command to a law enforcement officer, which allows the law enforcement officer to personally go and search and seize things (or people), while overriding some rights that would normally prevent this. Normally it is issued by a court. Generally there is no way to challenge a warrant to prevent its execution, because it is not disclosed to the target before it's executed (i.e., a law enforcement officer shows up with the warrant and begins executing it immediately, by force if necessary).
(Edit: I wrote above that it's risky to comply imperfectly with a subpoena and then argue in court that this was reasonable, but usually if a lawyer gives a professional opinion that the subpoena is invalid or overbroad for some reason, then the recipient of the subpoena won't be punished for following that advice. The lawyer may also attempt to negotiate directly with the issuer of the subpoena, for example by sending a letter explaining why the the subpoena appears to be invalid. The legal standards for issuance of subpoenas are also pretty broad. For civil litigation, which is not what DoJ is doing here, they are set out in https://www.law.cornell.edu/rules/frcp/rule_26; notably, they can be issued to third parties.)
> This url does not exist. Was this response generated by an LLM?
No, its just that HN’s automatic linkification continues until it breaks on whitespace, so if you type punctuation (here, the “;”) after a link with no intervening space, it gets included in the URL.
Not a dumb question: a subpoena is an order to provide information or access, while a warrant is a court-issued document authorizing the government (or an agent of the government) to perform an act (e.g., an arrest, or seizure of an item).
Subpoenas can be issued by attorneys (including prosecuting attorneys) as part of the investigative and discovery processes.
Subpoenas are orders, but they're not necessarily court-issued. Warrants, on the other hand, are court-issued -- the police can't issue warrants on their own in the US.
I realize this comment is a little ambiguous: the order in the warrant case is an order by the court to the court's officers to perform an arrest, seizure, etc. It's not an order for you (the subject of the warrant) to comply.
