A Chinese operative was arrested in the US for spying on the family of Taiwan's President Lai Ching-te, a case that hardens the view in Washington that Beijing runs surveillance networks on American soil.

• A 34-year-old Chinese-American real estate agent from Irvine, California was arrested at Los Angeles airport and appeared in federal court.
• The charges are acting as an unregistered agent of the Chinese government and watching family members of a senior Taiwanese official.
• The target was the son of Taiwan's president, meaning Beijing's pressure on Taiwan is now reaching into US neighborhoods.
• Senators Rick Scott, Pete Ricketts and Marsha Blackburn all called it proof that China is infiltrating the US and a direct threat to national security.
• The case feeds the push to treat Chinese spying inside the US as a security problem, not just a diplomatic one.

Outlook: Expect louder calls in Congress for tougher counter-espionage measures and more friction in US-China relations as the prosecution moves ahead.