China's new national security law, enacted last week by the National People's Congress, the country's parliament, is worrying on several levels, both because of what it says and because of what is left ambiguous.

To soothe local worries, Hong Kong's Secretary for Justice, Rimsky Yuen, described the new law as little more than a "declaration of principles" that is "a blueprint for overall national security." Similarly, one of his predecessors, Elsie Leung, called it "framework legislation."

Indeed, the law is striking for its lack of specificity. But it is chilling in its sweep, potentially including every sphere of activity, foreign as well as domestic, within the realm of national security. It provides for a national security review mechanism that would cover all activities "that impact or might impact national security," from foreign investment to Internet information technology.