Nuland questioned who would enforce a demilitarised zone, given that there was little appetite for a large international peacekeeping force. Absent that or other robust security guarantees, Putin would simply bide his time and then restart the war, she said.

“Putin will just wait, rest, refit and come for the rest,” Nuland said.

Another problem with Vance’s vision is that it ignores the will of the Ukrainians, who insist they want to keep fighting to regain their lost territory, said Luke Coffey, a senior fellow at the Hudson Institute, a conservative think tank.

“I don’t think he offered a realistic proposal for peace,” Coffey said. “He offered a plan for a Russian victory.”

Vance’s plan has worried Ukrainians. Oleksandr Merezhko, the chair of the Ukrainian parliament’s foreign affairs committee, called the proposal “election rhetoric which will hardly stand the test of political reality”.

He said what was “conspicuously absent” from Vance’s description of Trump’s peace plan was “the issue of reliable security guarantees for Ukraine”.

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But Elbridge Colby, who was a Pentagon official during the Trump administration, said Vance’s plan was based on a realistic assessment of the current status of the war, which began in February 2022.

Colby said Russia was continuing to make significant progress in eastern Ukraine and counterattacking in Kursk, a Russian city that the Ukrainian military has occupied since last month. Wars usually end roughly along the line of contact between two opposing armies. And he said there was no plausible basis for thinking Ukraine would gain the upper hand.

Ukrainian President Volodymyr Zelensky on Saturday (AEST) denied Russia had retaken parts of Kursk, saying the earlier Ukrainian incursion there had served to slow Russian advances towards Donetsk and Kharkiv. “So far, we have seen no serious [Russian] success,” he added, according to Reuters.

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Colby said Vance’s statement ruling out NATO membership for Ukraine was the right policy choice and that an expansion of the alliance further east was not in US security interests. But he said Vance’s comments do not rule out economic and social ties with Europe, or even other security contributions.

“Senator Vance is being realistic and putting out forthrightly a realistic basis for ending the conflict,” he said, “while other people are engaged in a kind of irresponsible fantasy.”

Of course, it is not entirely clear that Vance was speaking for Trump. At times, Trump has embraced Vance’s policy positions, and other times pushed back on them. Coffey said that during his presidency, Trump showed that he often ignored advice from top officials, and there was no guarantee that Vance’s plan would be adopted. Still, he added, the two men appear in alignment.

“Listening to what Trump has said, and listening to what Vance has said, I would say Vance is probably in the ballpark,” Coffey said. “But what matters at the end of the day is what Trump does or does not want to do.”

This article originally appeared in The New York Times.

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