A revised law dramatically expanding China's definition of espionage comes into force on Saturday, giving Beijing more power than ever to punish what it deems threats to national security. The law provids authorities "near total discretion in the name of combatting national security threats", Jeremy Daum, senior research fellow at Yale's Paul Tsai China Center, tells AFP. "The way that this law is written is in an intentionally vague manner that allows, and in fact requires selective enforcement... It's been a question of will, of when they want to go after people," he adds. SOUNDBITES