From the Brookings report, “Is seeing still believing? The deepfake challenge to truth in politics,” with a nod to the Marx Brothers’ classic Duck Soup:

If AI is reaching the point where it will be virtually impossible to detect audio and video representations of people saying things they never said (and even doing things they never did), seeing will no longer be believing, and we will have to decide for ourselves—without reliable evidence—whom or what to believe. Worse, candidates will be able to dismiss accurate but embarrassing representations of what they say are fakes, an evasion that will be hard to disprove….

Faced with this epistemological anarchy, voters will be more likely than ever before to remain within their partisan bubbles, believing only those politicians and media figures who share their political orientation. Evidence-based persuasion across partisan and ideological lines will be even more difficult than it has been in recent decades, as the media has bifurcated along partisan lines and political polarization has surged.