Concept
Who May Serve
Service of a subpoena
Who May Serve
Two questions decide whether a person may serve a subpoena: is the person at least 18 years old, and is the person a party? Rule 45(b)(1) allows any person who is at least 18 and is not a party to serve, so a proposed server must pass both.1 A server who is 18 or older and is not a party qualifies, and the rule asks nothing further about who that person is or what training the person has.
Because the rule stops there, the server need not be a United States marshal, a sheriff, or a licensed process server. A lawyer who needs a deposition subpoena delivered may hand it to a courier or a paralegal instead of waiting for an official, which keeps service quick and inexpensive. The federal criminal rule is built a little differently. Rule 17 allows service by the marshal, a deputy, or any other adult nonparty, and some districts by local rule require the marshal or a deputy marshal to do it. Where the prosecutor has a choice, the case agent is often preferred, because the encounter at the door may create a chance to interview the prospective witness.2 The civil rule, as quoted above, makes no such demand: an adult nonparty is enough.
The two questions guard against different problems. The server will later vouch for what happened. When proof of service is needed, a statement showing the date and manner of service and the names of the persons served is filed with the issuing court, and the server must certify it.3 The court therefore relies on the server's word about whether, when, and how the subpoena reached the witness. That reliance makes sense of the nonparty requirement. A party has a stake in showing that service was valid, and a certification from someone with that stake is worth less than one from a person with no interest in the outcome. The age floor protects something more basic: a server mature enough to complete the delivery and to give a certified account of it.
The nonparty test turns on party status alone. An employee of a party's lawyer, whether a paralegal, a secretary, or a messenger, is not a party to the lawsuit, however much loyalty the person owes to the side that pays the salary, and the rule does not ask whether the server is friendly to the cause. A question that stresses the server's employment at the plaintiff's firm invites you to find a disqualification that the text does not contain.
Service fails when either question is answered the wrong way, and the two failures are independent of each other.
Passing one question never rescues a failure on the other. An adult party and a nonparty minor are both disqualified, for different reasons, and a careful answer names the question each server failed.