For a glimpse of where artificial intelligence is headed in election campaigns, look to India, the world’s largest democracy, as it starts heading to the polls on Friday.

An A.I.-generated version of Prime Minister Narendra Modi that has been shared on WhatsApp shows the possibilities for hyperpersonalized outreach in a country with nearly a billion voters. In the video — a demo clip whose source is unclear — Mr. Modi’s avatar addresses a series of voters directly, by name.

Down the ladder, workers in Mr. Modi’s party are sending videos by WhatsApp in which their own A.I. avatars deliver personal messages to specific voters about the government benefits they have received and ask for their vote.

Those video messages can be automatically generated in whichever of India’s dozens of languages the voter speaks. So can phone messages by A.I.-powered chatbots that call constituents in the voices of political leaders and seek their support.

Such outreach requires a fraction of the time and money spent on traditional campaigning, and it has the potential to become an essential instrument in elections. But as the technology races onto the political scene, there are few guardrails to prevent misuse.

Chatbots and personalized videos may seem more or less harmless. Experts worry, however, that voters will have an increasingly difficult time distinguishing between real and synthetic messages as the technology advances and spreads.