President Bush this week declared a national emergency based on an "extraordinary threat to the national security."
This might sound like a code-red, call-out-the-national-guard, we-lost-a-suitcase-nuke type of alarum, but in reality it's just a bureaucratic way of ensuring that the Feds can continue to control the export of things like computer hardware and encryption products.
And it happens every year or so.
If Bush didn't sign that "national emergency" paperwork, then the Commerce Department's Bureau of Industry and Security would lose some of its regulatory power. That's because Congress never extended the Export Administration Act after it lapsed (it's complicated).
President Clinton did the same thing. Here's an longer version of his "national emergency" executive order from 1994.
As a side note, encryption export rules have been dramatically relaxed since the oppressive early days of Janet "Evil PCs" Reno, Al "Clipper Chip" Gore, and Louis "ban crypto" Freeh. But they still exist. Here's a summary.