Why politics demand stern Obama reaction
The ³ÉÈË¿ìÊÖ has been told by a senior administration official that a Saudi tip-off led to the discovery of the "sinister" devices on cargo planes bound for the United States. They were rather curious - ink cartridges smeared with white powder with and some electronics attached.
We don't yet know exactly what they were, or what sort of damage they could do.
Still, whenever President Barack Obama has tried to play down a threat or put it in context he has been attacked with breathless horror, as though a stiff upper lip was somehow giving in. So there is no mileage in doing anything but playing it up to the maximum.
Mr Obama was the first to say that the devices contained "explosive materials", though off-the-record briefings in Britain suggested the one at East Midlands Airport didn't. Mr Obama didn't use the word "bomb" though. It was made clear he was told about "a credible terrorist threat" just seven minutes after the discovery of the device in Britain. A photographer was on hand to capture later, stern-faced meetings.
But on first sight at least, while this is nasty stuff it doesn't look like a fully-fledged plot against America. There have been various theories. A dry run? Well, you generally do a dry run when human agents are at risk of being discovered, not envelopes.
It doesn't mean rather stupid terrorists could not have planned a dry run, but it doesn't make any logical sense. It doesn't seem these "proto-bombs" could bring down an aircraft or were set to do so. The dry run could have been designed to cause exactly the sort of disruption and media coverage that has indeed followed.
But to me it looks like a rather bizarre attempt at a long-distance letter bomb. Even with the mid-terms round the corner, I doubt it will have much political impact, but Mr Obama was probably politically wise to make it look as though he is in personal charge of a grave situation.
Leaving others he has appointed to get on with it may be his instinct, but delegation is seen by the media here as failure.
I’m Mark Mardell, the ³ÉÈË¿ìÊÖ's North America editor. These are my reflections on American politics, some thoughts on being a Brit living in the USA, and who knows what else? My 
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