A top Hillary Clinton campaign aide called Bernie Sanders a 'doofus' in leaked email

John Podesta, Hillary Clinton's campaign manager, called Bernie Sanders a "doofus" in an email uncovered by Wikileaks on Wednesday.

"Can you believe that doofus Bernie attacked it?," the message goes, in an exchange that was part of an email chain from December 2015.

In the email, Podesta and others were responding to the climate change deal - reached during a summit attended by negotiators from more than 190 countries that month.

At the time, Bernie Sanders criticized the deal, saying it did not go far enough.

"The planet is in crisis. We need bold action in the very near future and this does not provide that," Sanders, said at the time, during what turned out to be a brutal Democratic primary between the Vermont senator and his then-rival, Hillary Clinton.

It's the latest wrinkle in what has been a long-playing scourge on Clinton's presidential campaign. The hacked emails ostensibly targeted organizations and individuals associated with the Democratic Party - many of which have generated unsavory headlines and turmoil within the party.

Sanders has since endorsed Clinton's bid for the White House and has attended several campaign events on her behalf.