A military service affidavit is required in cases where the defendant has not filed an Appearance form with the court clerks office by the time of the court hearing. The purpose is to protect men and women serving in the U.S. military from getting a court judgment against them without first receiving notice of the lawsuit and a chance to defend the case. The affidavit gives the court the necessary facts to find that the defendant is not in the U.S. Military.