Because Missouri defines work product in criminal procedure only in regard to the attorney's opinions, theories or conclusions, the Missouri Supreme Court found that because grand jury proceedings do not take place before an indictment is filed, the discovery rules for criminal proceedings do not apply.

"Historically, a lawyer is an officer of the court and is bound to work for the advancement of justice while faithfully protecting the rightful interests of his clients," Judge Patricia Breckenridge wrote. "In performing his various duties, however, it is essential that a lawyer work with a certain degree of privacy, free from unnecessary intrusion by opposing parties and their counsel. Proper preparation of a client's case demands that he assemble information, sift what he considers to be the relevant from the irrelevant facts, prepare his legal theories and plan his strategy without undue and needless interference. ... Were such materials open to opposing counsel on mere demand, much of what is now put down in writing would remain unwritten. An attorney's thoughts, heretofore inviolate, would not be his own. Inefficiency, unfairness and sharp practices would inevitably develop in the giving of legal advice and in the preparation of cases for trial. The effect on the legal profession would be demoralizing. And the interests of the clients and the cause of justice would be poorly served."