“There will be a Russia point of view, which will have to be considered when the war in Ukraine has ended,” he said during a book launch for his latest work, Leadership: Six Studies in World Strategy.
The veteran Republican statesman said the overall approach to the war in Ukraine that was launched by Russia in February would need to shift focus to “political objectives as well the military situation”.
“One cannot simply continue fighting without an objective to which the various countries can relate,” he added.
“The Ukraine issue was composed when it started [in February] of two pieces: one, there was a part of Ukraine that Russia has annexed 10 years ago and the rest of Europe and America had acquiesced in that.
“The second issue is Ukraine as it existed on the day the Russian aggression and invasion started. I believe that if the defence of Ukraine reaches those borders — in other words, if it drives Russia off any conquest, then a negotiation could start about the future relationship.”
Having singled out Ukrainian President Volodymyr Zelenskyy as a voice urging Kyiv to recognise Russian demands, Mr Kissinger, who was US secretary of state between 1973-1977, said he did not have any proscribed views for how the Ukrainians might finish the war.
He pointed to a calculus that Mr Zelenskyy had himself spoken of that appeared to take into account Russian enclaves carved out in the confrontation in 2014.
“It was not that Ukraine should give up territory to Russia in order to achieve peace,” Mr Kissinger said.
“We are not at that point yet because about 20 per cent of Ukrainian territory is now occupied by Russia and that has to be returned before one can speak of a settlement.”
Mr Kissinger added that the Ukrainian president had made reference to a “great victory” if Russian forces were pushed back to the February frozen conflict lines.
“[Mr Zelenskyy] said if we reach the borders, it will be a great victory. And after that, we will still argue for the return of the remaining 7 per cent of the territory.”
With a long history of travel after holding the influential office of secretary of state, Mr Kissinger has become an unofficial adviser and sounding board for many leaders.
He first met Russia's President Vladimir Putin before he rose to the country's highest office and said the conflict could not have been predicted from the discussions he had with the Russian leader over the years.
“I'm surprised at the scale of the aggression against Ukraine — it did not fit into the nature of our discussions,” Mr Kissinger said.
“The Ukraine issue did not just arise. The West was intent at that time intent on offering Nato membership to Ukraine because that meant the whole area between Berlin and the Russian border was going to be filled by Nato, including all the territory from which aggression was launched against Russia throughout its history.
“That was the underlying Putin concern against Nato, as I understood it, but it did not justify the attack and the rejection of a comprehensive diplomacy.”
Germany will have an important role in rebuilding the Europe that is now emerging, including the rebuilding of Ukraine itself after the war, which will require some form of Marshall Plan-type assistance, he added, referring to the post-Second World War US programme that pumped funding into Europe.
“The German government hasn't been able to jump into this with a full programme — it will be so different from what it has had to do in the previous period.”