Some documents that were leaked contained sensitive references to foreign heads of state. This could anger them into taking revenge on us, or worse. So to answer your question, yes, WikiLeaks can very well be a threat to U.S. National Security.
National threat to the security
By claiming Iraq had weapons of mass destruction, making it a threat to national security
You can find information about National Security on the government's national security website which posts the current threat level and additional information pertaining to national security.
The leaking of sensitive communication between countries can threaten national security, government officials claim. They are kept classified for a reason. On the other hand, without WikiLeaks, some corruption would not be exposed.
Perhaps that is irrelevant as they are bound to end up on "WikiLeaks".
Planning
Planning
The Soviet Union.
disadvantages: threat to national security
planning
planning
planning