Former US Secretary of State Henry Kissinger has told Sky News he sees no path to negotiation with the Islamic State (IS).
"I think it has to be defeated. During the Second World War, nobody said, 'What is the solution for dealing with Hitler?'
"This is an organisation which has engaged in mass murder on television in the killing of prisoners.
"But there are many other groups in the region with which we should negotiate."
Dr Kissinger, 92, is viewed by many as the wise man of US politics having spent six decades immersed in foreign policy serving Presidents Richard Nixon and Gerald Ford.
He declined to reveal who he'd like to see as the 45th US president.
With a strong public wave of anger towards politicians, anti-establishment figures such as Donald Trump have been surging in the polls.
It is possible that someone with no political background could end up in the White House.
Dr Kissinger says that would present challenges.
"It's a totally unprecedented move to have somebody without any experience in government or any previous participation in the political dialogue.
"(Trump) appears on the scene and obviously evokes an enormous response.
"That is something that I'm sure all our political figures are reflecting on very seriously now.
"It's not what anybody expected. It's not the way normally you would bring about a political change.
"His personality is evoking something that most people didn't know was there - at this magnitude."
But the elder statesman said he did not think Trump would win the Republican nomination.
After President Obama's 2009 landmark speech in Cairo reaching out to the Islamic world, Dr Kissinger likened the then-new leader to a chess player.
He said he had "no quarrel" with that speech being his first move.
But does he think Obama has played a good game since?
"To the extent that the United States is a world leader, I have no quarrel - indeed I support the attempt - to define a moral basis for that claim.
"But the dilemma of any policy maker is that moral values aren't absolute. Political action is contingent.
"So I think I have disagreed with Obama on his reluctance to state a strategic position for the United States and as a result he has created the impression of an American withdrawal even while we still had forces there."
In 1972, Dr Kissinger stunned the world by paving the way for Nixon to meet his Chinese counterpart Mao.
At the time that seemed unthinkable.
It earned him a reputation a big diplomacy advocate.
But on two major current issues - North Korea and the Islamic State - Dr Kissinger told us he does not think there is a diplomatic solution - a strong sign perhaps of just how much the world has changed.