Noam Chomsky, the world's leading dissident intellectual, has warned the grievances exploited by far-right extremists need to be taken seriously by their left-wing opponents.
Speaking at the annual Amnesty International lecture in Belfast, Professor Chomsky noted: "There is now a mass of people with real grievances who want answers and are not receiving them. A common reaction in elite educated circles and much of the left is to ridicule the right-wing protesters, but that is a serious error.
Dr Chomsky said history had shown it was a grave mistake not to answer the calls of people mired in poverty, who are susceptible to the argument that rich liberals are giving their money to illegal immigrants and the shiftless poor.
He gave his sombre address on Friday evening to a capacity audience at Queen's University.
Later, he forecast that the rift between Washington and Edinburgh over the release of the Lockerbie bomber would blow over. Responding to a question from the Sunday Herald, he suggested American anger was bluster and the Obama administration would have been relieved that Abdelbaset Ali al-Megrahi had dropped his appeal.
"The appeal was going to bring in evidence from US intelligence casting serious doubt on the whole trial," he said.
He added that he had sympathy with those who suspect a politically driven cover-up concerning Lockerbie.