Professor Noam Chomsky said that Donald Trump supporters could be enticed to vote Democrat again if the Bernie Sanders movement offered a real program for "hope and change".
On the same evening that vice president Joe Biden said he might run for president in 2020, Mr Chomsky told the crowds at Democracy Now!’s 20th anniversary event that reigniting a "militant labour movement" could swing the next election.
Mr Chomsky, the renowned scientist and philosopher, said American workers have been beaten down for decades with weakened labour unions and stagnant wage growth since neo-liberal policies were instituted in 1979. President Obama’s supporters in 2008 and 2012 were voting for his slogan of "hope and change", but were disappointed.
"The working class has suffered from it. They had a real need for hope and change. Well, they didn’t get hope and they didn’t get change," he said.
"I don’t often agree with Sarah Palin, but she nailed it when she came along and said, Where is all this hope-y, change-y business?"
But the professor said that if young people and activists revived a strong labour movement, which could overcome racial conflict like it did in the 1930s, then the workers’ favour could be won back.
"Suppose people like you, the Sanders movement, offered an authentic, constructive program for real hope and change, it would win these people back," he said.
"I think many of the Trump voters could have voted for Sanders if there had been the right kind of activism and organization. and those are possibilities. It's been done in the past under much harsher circumstances."
Alan Greenspan, the former chairman of the US Federal Reserve, testified to congress that the success of the American economy was based on "growing worker insecurity". Mr Chomsky pointed to this as an example of how workers have continued to suffer, even if the stock market is nearing record highs. It was one major reason why people voted for Mr Trump.
"You should also bear in mind what a remarkable phenomenon the Sanders campaign was. Here’s somebody unknown, came from nowhere, was using words like socialism which used to be a real curse word, no corporate or media support, no support from the wealthy, everything that has been crucial to win elections."
"He could have taken it over [the Democratic party] if it hadn’t been for shenanigans that you know about," he said, perhaps alluding to the Democratic National Committee’s alleged attempts to smear the Vermont senator.
He added that there have been many advances and achievements over the past 50 to 60 years, for women’s and civil rights, for gay people and in terms of people’s efforts to counter aggression.
"That means struggles today start from a much higher plane than they did many years ago," he said.
"Even the election itself suggests major opportunities. For one thing, the Democrats had a considerable majority in the vote," he said, referring to Ms Clinton’s lead of more than 2.6 million people in the popular count.
"And if you look at younger voters, the people who will shape the future, they were overwhelmingly anti-Trump and even more overwhelmingly pro-Sanders."
He said the country was founded on "two incredible crimes" - the virtual extinction of indigenous people and the most vicious form of slavery in history, which was the foundation for wealth and economic development.
"When Donald Trump talks about 'making America great again', for many people it wasn’t that great, it was quite the opposite," he said.
It will be up to young people, he said, to lead Americans towards a "decent and civilised world".