Jim Harper noted yesterday that the Department of Homeland Security (after lengthy review) has decided to scrap its color-coded alert system. The change is long overdue--the alerts implied, absurdly, that danger was equally distributed across the nation. The fact that the Department never used the blue and green threat levels (general and low risk), which most accurately describe the true danger most Americans face from terrorism, showed the systems' inherent threat inflation. Eventually, everyone started ignoring the threat level, officials stopped changing it, and system became a charade.

Jim argues that, in place of the colors, the Department should inform "the public fully about threats and risks known to the U.S. government," treating us like adults with a shared responsibility for protecting ourselves. According to a report from the National Journal's Chris Storm, DHS agrees, sort of.  Storm links to a DHS document on the new warning policy, which states:

• DHS will implement a new system that is built on a clear and simple premise: When a threat develops that could impact the public, we will tell you.  We will provide whatever information we can so you know how to protect yourselves, your families, and your communities.

• The new system reflects the reality that we must always be on alert and be ready.  When we have information about a specific, credible threat, we will issue a formal alert providing as much information as we can.

• Depending on the nature of the threat, the alert may be limited to a particular audience, like law enforcement, or a segment of the private sector, like shopping malls or hotels.

• Or, the alert may be issued more broadly to the American people, distributed — through a statement from DHS — by the news media and social media channels.

• The alerts will be specific to the threat.  They may ask you to take certain actions, or to look for specific suspicious behavior.  And they will have an end date.

• This new system is built on the common-sense belief that we are all in this together — that we all have a role to play — and it was developed in that same collaborative spirit.

The first bullet point embraces maximum information sharing, but things get hazier after that. In the end, it's not clear when DHS will warn all of us, warn some of us, or just warn police. Nor do we get much indication about what information warnings will include. Unlike Jim, though, I think that's fine. Actually, there are a couple reasons why I hope DHS winds up being tighter-lipped.

First, most threat warnings are false alarms. A government that publicized every warning received by intelligence agencies would swamp the public with confusing and frightening information that people would have to learn to ignore. Better to reveal only intelligence that has been vetted.

Second, the theory of providing the public maximum information about danger (often a cover for the CYA imperative to have warned the public if an attack does occur) in practice easily degenerates into vague exhortations to be vigilant, which are almost as bad as the color-coded threat warnings. The difficulty is that the threat information is vague and that authorities worry that revealing too much detail will give away sources. The warning issued to Americans going to Europe last October, is an example, as I discussed here.

Given that such general warnings create false leads, cancelled travel, anxiety, and harassment, they may do more harm than good.  In response to this argument, people point to the vigilant airline passengers who subdued the shoe and underwear bombers or the Times Square vendors who called the cops after Faisal's Shazhad's car failed to explode. But, at least since 2001, we hardly need the government to tell us to respond to people lighting their underwear on fire on international flights or cars burnings in Times Square. The theory that increased public vigilance is always a good thing needs testing.