CHICAGO — Former President Barack Obama was back home in Chicago on Wednesday with an urgent warning about disinformation.

The conversation took place at the University of Chicago Institute of Politics after they teamed up with The Atlantic.

“The way I define disinformation is if you have a systematic effort to promote false information, suppress true information for the purpose of political gain, financial gain,” Obama said.

The former president telling this conference held at the University of Chicago Institute of Politics that normal debate of ideas is fine, but systemic disinformation is destructive.

“It is difficult for me to see how we win the contest of ideas if we don’t agree on facts,” Obama said.

The former president also offered thoughts about Russia’s attack on Ukraine. He said Vladimir Putin’s aggression should serve as a reminder to the world that democracy is fragile.

“It is a tragedy of historic propositions,” Obama said. “It is a bracing reminder for Democracies that had gotten flabby. What’s happening there is not isolated. What we’re seeing is a reversion back to old ways about thinking about power, place and identity.”

Wednesday’s event came after former President Obama attended the White House’s ceremony Tuesday to celebrate the 12th anniversary of the Affordable Care Act.