Here's the recipe for a scary, post-9/11 news story about liberties vs. security:

• First, find a legitimate domestic surveillance program. Make sure it's one most Americans ignore - the more obscure, the better. It doesn't matter if the courts have ruled it constitutional. It doesn't matter if it helps fight crime or protect national security.
  
  
• Next, find an "expert" to denounce the program as an unnecessary expansion of executive authority. Rail about the potential for abuse (even when there's no evidence of actual abuse). Argue that the program could be a threat, even if it hasn't, in fact, been misused.
  
  
• Finally, stimulate the "Luddite response" - a fear of technology. Rant about how the information age is destroying any hope of privacy. More information and technology equals power. And with more power comes more abuse.

Combining these ingredients is guaranteed to shock sensibilities and spark congressional hearings. It's been done many times, starting with the tools authorized in the Patriot Act to fight terrorism, like delayed-notification warrants.

U.S. military domestic investigations are the latest intelligence and law enforcement tool to receive the treatment. A spate of recent news reports revealed that the armed forces use "national security" letters to request business records, such as phone and bank data. It sounds scary, but it shouldn't.

The military has a legitimate, limited mission to conduct intelligence inside the United States. It is written into law and funded by Congress. National security letters are perfectly legal, and the Defense Department is authorized to issue them. Requesting business records is a common intelligence and law enforcement practice and does not in many cases require a warrant.

Finally, there is a domestic security threat to worry about. On 9/11, there was an attack on American soil, and others have been plotted since then. Keeping America safe, free and prosperous requires both liberty and order. Protecting the safety and freedom of Americans is not served well by simply demonizing security.

James Carafano is Senior Research Fellow for National Security and Homeland Security at The Heritage Foundation and author of the new book "G.I. Ingenuity."