Belfer Center Senior Fellow David E. Sanger examines the latest news on the scope and scale of Russian cyberwarfare.

Belfer senior fellow and National Security Correspondent David E. Sanger discusses the wide disconnect between President Trump and U.S. intelligence during the Helsinki summit.

The Pentagon has quietly empowered the United States Cyber Command to take a far more aggressive approach to defending the nation against cyberattacks, a shift in strategy that could increase the risk of conflict with the foreign states that sponsor malicious hacking groups.

More than 30 high-tech companies, led by Microsoft and Facebook, announced a set of principles on Tuesday that included a declaration that they would not help any government — including that of the United States — mount cyberattacks against “innocent civilians and enterprises from anywhere,” reflecting Silicon Valley’s effort to separate itself from government cyberwarfare.

A newly drafted United States nuclear strategy that has been sent to President Trump for approval would permit the use of nuclear weapons to respond to a wide range of devastating but non-nuclear attacks on American infrastructure, including what current and former government officials described as the most crippling kind of cyberattacks.