N.D. Cent. Code § 44-09-09
The senate and each member thereof, unless excused for cause, shall meet at the senate chamber on the day assigned to hear the impeachment and organize as a court for the trial of the same. Such organization must be held and deemed to be perfected when the presiding officer of the senate and all members thereof, not excused, have taken the oath or affirmation prescribed. No member may sit in the trial or vote upon such trial until the member has taken such oath or affirmation. The oath or affirmation must be administered by the secretary of the senate to the presiding officer thereof and by the presiding officer to each of the members of the senate. The senate sitting as a court upon the trial of an impeachment has the same power to compel the attendance of its members as when engaged in the ordinary business of legislation.
N.D.C.C. § 44-09-09