Johnson repeatedly confirmed with the media-relations folks at these agencies that it was OK for him to photograph the buildings — as it is for any member of the public — but word hadn't filtered down to the guys with guns.

Johnson writes: "After I took this photo of a public walkway in front of the (Department of Energy) building, four armed guards surrounded me and my bike. I was ordered off my bicycle and told to hand over my camera. 'Where is your identification? Why are you taking photos of our building?' an officer asked me. I explained my role as a reporter and asked what rules I had broken. 'You are suspicious, and we are in a post-9/11 world,' he said. The four officers surrounded me right here, directly in front of the building entrance."

Here's the thing: They had no authority to do this.