A national voter group filed a lawsuit against Secretary of State Mike Coffman alleging that as many as 30,000 voters had been purged from the rolls in Colorado. According to the Advancement Project, which filed the lawsuit in Federal District Court in Denver, Mr. Coffman, a Republican, illegally disqualified thousands of voters by removing them from voter rolls within 90 days of Election Day, which is prohibited by federal law. The lawsuit also alleges that a few thousand new voters were improperly disqualified because election officials did not follow federal guidelines in seeking to verify their home addresses. Instead, the new voters’ registration was canceled if a notice sent by election officials to their address was returned within 20 days, the Advancement Project says. The lawsuit seeks to reinstate those voters who have been illegally purged from the rolls. Richard Coolidge, a spokesman for the secretary of state’s office, would not comment on the lawsuit.