To whose god are you swearing?

Baffled. I am truly baffled that there is no standard witness or juror’s oath or affirmation in our court system. Nor does there appear to be a standard court instruction to inform those to be sworn in of any alternative affirmation. Considering the number of different religious sects, organizations, beliefs, non-beliefs and churches in Middle America alone, the Missouri courts seem to believe that witnesses and jurors can only swear to a single god. What is wrong with this picture?