Hackers released a treasure trove of unpleasant internecine emails on the eve of the Democratic National Convention. The Democratic Party chairwoman was out of a job and tensions between Hillary Clinton and Bernie Sanders supporters were reignited just as the Democrats were trying for a prime-time show of unity. Who were the hackers? Security experts inside and outside the government have pointed the finger at Russia. So, was this an act foreign aggression playing out on a strange new battlefield?