What do we do about deepfake video?

There exist, on the internet, any number of videos that show people doing things they never did. These videos are called deepfakes, and they're made using a particular kind of AI. Inevitably enough, they began in porn – there is a thriving online market for celebrity faces superimposed on porn actors' bodies – but the reason we're talking about them now is that people are worried about their impact on our already fervid political debate. Those worries are real enough to prompt the British government and the US Congress to look at ways of regulating them. The video that kicked off the sudden concern last month was, in fact, not a deepfake at all.