A federal judge decided Monday that he will consider adding a “terrorism enhancement” to the prison terms of two white supremacists who prosecutors said plotted to carry out deadly violence at a Virginia guns-rights rally last year to provoke what one of them called “a full-blown civil war.”

Patrik Mathews, 29, and Brian Lemley Jr., 35, pleaded guilty to firearms- and immigration-related charges in U.S. District Court in Greenbelt, Md., and are scheduled to be sentenced Thursday. After hours of legal arguments Monday, Judge Theodore D. Chuang sided with prosecutors, ruling that the two can be sentenced to prison terms that are longer than the normal maximums for their admitted offenses.