A warning by tech billionaire Peter Thiel five years ago about young voters and socialism was resurfaced after this week's election wins by New York Mayor-elect Zohran Mamdani and other Democrats.

The PayPal co-founder sent a private message in 2020 offering a theory to explain why millennials were more open to socialist ideas than other generations, and Thiel argued that student debt and the housing costs were to blame for the shift, reported Business Insider.

"When 70% of Millennials say they are pro-socialist, we need to do better than simply dismiss them by saying that they are stupid or entitled or brainwashed; we should try and understand why," Thiel wrote in a January 2020 email to top Facebook officials, including CEO Mark Zuckerberg, President of Global Affairs Nick Clegg and venture capitalist Marc Andreessen.

Billionaire investor Chamath Palihapitiya posted a screenshot of the email on X after Mamdani, a self-described Democratic Socialist, defeated former New York governor Andrew Cuomo, who ran as an independent, and Republican Curtis Sliwa to become the next mayor of the nation's largest city.

"Too much student debt and lack of affordable housing keeps young people with negative capital for too long," Palihapitiya wrote on X. "And without a stake in the capitalist system, they will turn against it."

Thiel, often described as a libertarian, spoke in support of President Donald Trump at the 2016 Republican National Convention and has been a mentor to Vice President JD Vance.

"From the perspective of a broken generational compact, there seems to be a pretty straightforward answer to me, namely, that when one has too much student debt or if housing is too unaffordable, then one will have negative capital for a long time and/or find it very hard to start accumulating capital in the form of real estate; and if one has no stake in the capitalist system, then one may well turn against it," Thiel wrote in his email to Facebook leaders.