Recently, departments have been pushed to institute mandatory arrest guidelines. In theory, these two approaches are on opposite ends of a continuum on the use of discretion. This research examines the training police officers from four departments have received, and how it affected their attitudes on intervention. The attitudes are then discussed in conjunction with mandatory arrest guidelines. Results indicate trained officers may be resistant to mandatory arrest guidelines; whereas, untrained officers are more likely to endorse them. 3 tables, 1 figure, and 16 references. (Author abstract)