Faking a clear, unbroken closeup of a recognizable person has never been a serious option before this. Even when Hollywood had likeness rights and massive budgets, it resorted to rewrites and old B-roll footage when actors died mid-shoot. When people wanted to slander politicians, even state actors with Cold War budgets, they edited photos, faked audio recordings, or staged candid, hard-to-see footage. In the modern era of CGI and digital video editing, bad actors still resorted to misleading edits and out-of-context clips. This, though, is 20 seconds of clear, closeup video of an incredibly famous face. And the fake was good enough that even placed in an art exhibition centered on something that never happened, some viewers thought it was real footage.
I don't share the popular paranoia that deepfakes of politicians are going to start upending democracy; there have always been plenty of people fervently convinced by manipulative video, altered pictures, or simple "somebody said so" lies. What's new is the increasing difficulty of proving truth in the most trusted contexts. Validating even a very narrow claim like "at some point in the past, for some reason, the President said this exact sentence in front of a video camera" is increasingly difficult.
The business model works on "most" people, but not all of them. You can't fight a Fox News with an Air America. It's been tried, more than once. When deepfake material comes to light at the expense of a Democratic president, rest assured, most people aren't going to bother demanding the White House's public key.
All they'll know is what they heard from the talking heads on their news channel of choice: "Well, I don't know, Sean, but a lot of people are saying it's real."
Ability is what interests me most. Faking this sort of content - a continuous, closeup shot of the President saying something - has basically never been possible before. If a total stranger had showed you this video in 1969, it would have been clearly authentic. Not clearly truthful, you wouldn't trust that the landing had really failed as opposed to e.g. Nixon recording speeches for both outcomes. But you could be pretty sure it wasn't an imposter or an edit or anything except the real Nixon on camera.
Deepfakes challenge that ability, but I don't think they'll destroy it. Official sources will sign video. Untrusted sources will use verified timestamping and other methods to prove specific claims about their footage.
Actual knowledge, on the other hand, can't be destroyed by deepfakes because we already don't have it. There are a hundred ways to lie to people - with photoshopped images, deceptive editing, or just lying and having people trust that the evidence exists somewhere. People who aren't easily fooled today will become skeptical about video footage too. People who are easily fooled are already fooled, have been fooled since before photography straight through to the present, and will just stay that way.
"Banning political deepfakes" or anything similar is not just a case of closing the barn door after the horses have left, but without ever getting the horses into the barn.
We do. Even today, very little of what you see in media is entirely real. The alterations are hardly ever as overt as Trotskyites being airbrushed out of Party publicity photos, but that doesn't mean they aren't being done.
Maybe an African-American person ends up looking a little blacker than they really are if they're being accused of a crime, or a little whiter if they're running for office. Maybe they just sound a little more or less "ethnic" depending on whether the press wants them in office or in jail. Or a video is sped up and slowed down at just the right moments to turn a journalist's uncomfortable question into an unprofessional partisan attack.
IMHO we can expect more of these cognitive shenanigans as the technology improves. Manipulation will be performed not just on the subjects in question, but on the contexts in which they appear.
So people learned that we shouldn't trust a photo of Martians, or a sound clip of the President confessing to murder, but should hold out for video. When footage of Rob Ford doing crack cocaine shows up, we believe it's real. And when an investigative reporter wants a verifiable record of something, they resort to a high-quality video.
Even if video deepfakes aren't any more realistic than image or audio fakes have been, they're important because there's no fallback. With perfect-accuracy photo and audio fakes, we'd have to be more skeptical. But with perfect-accuracy photo, audio, and video fakes, we'd suddenly be back to the pre-photography era when there was essentially no way for an untrusted source to convince you that something had happened. Deepfakes aren't flawless, we're not at that point, but the specifics of video are less important than the impact of having some medium which can't be convincingly faked.