2 U.S. Code § 388 - Subpena for attendance at deposition
Service of the subpena shall be made upon the witness no later than three days before the day on which his attendance is directed. A subpena may be served by any person who is not a party to the contested election case and is not less than eighteen years of age. Service of a subpena upon a person named therein shall be made by delivering a copy thereof to such person and by tendering to him the fee for one day’s attendance and the mileage allowed by section 389 of this title. Written proof of service shall be made under oath by the person making same and shall be filed with the Clerk.
A witness may be required to attend an examination only in the county wherein he resides or is employed, or transacts his business in person, or is served with a subpena, or within forty miles of the place of service.
Every subpena shall state the name and title of the officer issuing same and the title of the contested election case, and shall command each person to whom it is directed to attend and give testimony at a time and place and before an officer specified therein.
A subpena may also command the person to whom it is directed to produce the books, papers, documents, or other tangible things designated therein, but the committee, upon motion promptly made and in any event at or before the time specified in the subpena for compliance therewith, may (1) quash or modify the subpena if it is unreasonable or oppressive, or (2) condition denial of the motion upon the advancement by the party in whose behalf the subpena is issued of the reasonable cost of producing the books, papers, documents, or tangible things. In the case of public records or documents, copies thereof, certified by the person having official custody thereof, may be produced in lieu of the originals.