An attorney may be legally disqualified from representing a person or entity—often due to a conflict of interest. Attorney disqualification is a severe remedy, and has the potential to cause immediate harm by depriving a party of its chosen counsel, and disrupting court proceedings. Thus, a party requesting disqualification of an attorney generally has a high burden of proof, and must establish with specificity the basis for disqualification.

To meet this burden, mere allegations of a general conflict of interest, or of unethical conduct or evidence showing a remote possibility of a violation of the state’s disciplinary rules of ethical conduct will not suffice. While the state’s disciplinary rules are often not binding in such matters, courts look to them as guidelines in determining whether an attorney’s conduct requires disqualification.

In Missouri, the disqualification of an attorney from representing a client due to conflicts of interest is considered a drastic measure due to its significant impact on the client's right to chosen counsel and the potential disruption to court proceedings. Consequently, the party seeking an attorney's disqualification bears a substantial burden of proof. They must provide specific and convincing evidence that the attorney's continued representation would be inappropriate. General allegations of conflict or unethical behavior, or evidence that suggests only a slight chance of a violation of ethical rules, are insufficient grounds for disqualification. Missouri courts may refer to the state's Rules of Professional Conduct for guidance when determining whether an attorney's behavior warrants disqualification, but these rules are not directly enforceable in disqualification proceedings. Instead, they serve as a benchmark for assessing the attorney's conduct.