Red=Severe
Orange=High
Yellow=Elevated
Blue=Guarded
Green=Low
So, now we’re at orange, what has to happen for us to go red ? What color were we at before 9/11 ? And, will we ever be green, what would have to be going on for us to be green ?
This silly color system was not instituted until a while after 9/11. For it to reach green, we’d have to undergo some drastic societal change after which the megalomaniacs in Washington no longer find it useful to keep people frightened all the time.
If the Department of Homeland Security elevates our threat level to red, then the terrorists have already won. 
I realized after my OP that what I meant to say about 9/11,didn’t turn out right.
If the color code had been there, where would it have been ?
We’re probably never going to red, because then red would lose it mystique. People would say “So, this is as bad as it gets? Big deal!” The scale has to have that ominous last step… looming over us, reminding us that things can always get worse.
We’re certainly never going to green, as Friedo has already stated. Do we ever go to blue? I don’t recall it.
So, we actually have a two-color alert system, and both colors mean the same thing: “be scared enough not to question anything George W. does, but continue to work and buy things”
Orange also used to have the additional meaning of “buy more plastic and duct tape”, but I think people got tired of that.
Yep, we’re always going to hover between yellow and orange. Notice that the capture of Saddam Hussein did nothing to lower the terror color level–in fact, look, it went up! Surprise, surprise.
That’s only a surprise if you believed that Saddam Hussein had anything to do with terrorism against the United States.
If we had this terrorism color code, I’d bet we would have hit red on September 11, 2001, and likely stayed there for a couple days. Red basically means “it’s coming,” and it did that day.
As for the color code system itself: it angers me. The source of my anger is the order of the colors. Blue between Yellow and Green? Hello! It’s Red-Orange-Yellow-Green-Blue! And what about purple? Purple’s a mighty fine color. I can understand omitting Indigo, but dropping purple and swapping Green and Blue? Unforgiveable.
“The Department of Homeland Security today raised the threat level to Ultraviolet; however, the President asked all citizens to remain calm and go about their normal lives while continuing to avoid all previously demarcated radiation zones, bioweapon-contaminated areas, magma fields, spatio-temporal inversion anamolies, and extraterrestrial-occupied territories.”