  Conversational artificial intelligence (AI) disrupts how humans interact with
technology. Recently, OpenAI introduced ChatGPT, a state-of-the-art dialogue
model that can converse with its human counterparts with unprecedented
capabilities. ChatGPT has witnessed tremendous attention from the media,
academia, industry, and the general public, attracting more than a million
users within days of its release. However, its explosive adoption for
information search and as an automated decision aid underscores the importance
to understand its limitations and biases. This paper focuses on one of
democratic society's most important decision-making processes: political
elections. Prompting ChatGPT with 630 political statements from two leading
voting advice applications and the nation-agnostic political compass test in
three pre-registered experiments, we uncover ChatGPT's pro-environmental,
left-libertarian ideology. For example, ChatGPT would impose taxes on flights,
restrict rent increases, and legalize abortion. In the 2021 elections, it would
have voted most likely for the Greens both in Germany (B\"undnis 90/Die
Gr\"unen) and in the Netherlands (GroenLinks). Our findings are robust when
negating the prompts, reversing the order of the statements, varying prompt
formality, and across languages (English, German, Dutch, and Spanish). We
conclude by discussing the implications of politically biased conversational AI
on society.
