Five years ago, the U.S. Department of Homeland Security dropped its color-coded terror threat index developed after the 9/11 attacks amid widespread confusion and ridicule. So what did it do when tasked by Secretary Jeh Johnson in 2014 with measuring security along the country's borders? Agency staff proposed another system of reds, yellows and greens. "DHS should learn from its own history and avoid repeating this error," consultants said in a report.