13 years later, still a ways to go on sharing terrorist threats with public.

Back in 2011, then Secretary of Homeland Security Janet Napolitano ended the much maligned, and often ignored, color-coded terrorism threat advisory scale.

At that point, the homeland security advisory system had been "orange" for several years. Few seemed to know what orange" meant, and during the few times it was raised to red," the government was reluctant to share with the public details of why it was raised, and not much happened except for a lot of police collecting overtime pay.

The nonprofit Intelligence and National Security Alliance's homeland security intelligence council recently organized a tabletop exercise in order to see how well the national security apparatus shared information in the event of an attempted terrorist attack.

One of the findings in a report detailing the results of the exercise was that communication mechanisms with the American public needed to be reviewed.

The color-coded warnings were replaced by the national terrorism advisory system. Not once since its creation in April 2011 has an alert gone out to the general public.

The tabletop exercise scenario involved a terrorist cell that wanted to detonate a radiological dispersal device, also known as a "dirty bomb."

The intended target was the U.S. financial sector.

Caryn Wagner, chair of the alliance's homeland security intelligence committee, said the exercise's participants had a "uniformly negative" reaction to the question of whether they should notify the general public about the threat.

This brought up a question about the national terrorism advisory system: "Is it so narrowly drawn that it will probably never be used?" she asked at the alliance's Intelligence and National Security Summit in Washington, D.C.

The current system has two levels: One is an "imminent" threat. That is when the government has credible, specific information about an impending plot. The "elevated" warning is simply defined as a "credible" threat.

DHS has the responsibility to disseminate the information via alerts, induding social media.

Rand Beers, deputy assistant to the president and deputy homeland security advisor on the National Security...