Van Valkenburgh presided over the May 1918 trial of socialist activist Rose Pastor Stokes for alleged violation of the Espionage Act through speaking against war profiteering. Although Stokes proclaimed that she had "at all times recognized the cause of our entrance into the war" and "at no time opposed the war," Stokes was found guilty at trial and Van Valkenburg delivered a draconian sentence of 10 years' imprisonment, declaring Stokes to be "part of a systematic program to create discontent with the war" and to advance the cause of revolution.