Advances in machine learning are making it easy to create fake videos—popularly known as “deepfakes”—where people appear to say and do things they never did. For example, a faked video of Barack Obama went viral in April in which he appears to warn viewers about misinformation. Falsehoods already spread farther than the truth, and deepfakes are making it cheap and easy for anyone to create fake videos. When convincing fakes become commonplace, the public will also start to distrust real video evidence, especially when it does not match their biases. Unfortunately, the technology that enables deepfakes is advancing rapidly. Deepfakes will become easier to create, and humans will increasingly struggle to distinguish fake videos from real ones. Luckily, there is some hope that algorithms may be able to automatically detect deepfakes. Computer scientists have generally struggled to automate fact checking. However, early research suggests that fake videos may be an exception.