Bill Clinton has warned that some Brexit voters may only now be realising the impact of their decision.
The former US president said the choice between community and tribe will determine how the world meets the threat posed by climate change, inequality and other great challenges.
After being honoured by Dublin City University for his work on peace and reconciliation in Northern Ireland, Mr Clinton said he used the example of the Good Friday Agreement shamelessly around the world.
But he warned that the Brexit vote was about people thinking differences are more important that what they have in common.
“Now, there are lots of people who think they are less human,” he said.
“Now given the economic inequalities and the rapid pace of social change and all the upheaval that’s going on …. people are reassessing whether what we have in common is more important than our differences.
“A lot of people begged to differ.
“That’s really what the Brexit vote is all about.”