It may not be possible to send Vladimir Putin to face war crime charges at The Hague if he is the only person with whom the west has to negotiate an end to the Ukraine war, Emmanuel Macron has said. In a wide-ranging speech at an EU leaders conference in Bratislava, Slovakia, the French president also set out plans for a fast enlargement of the EU, reconciliation between the east and west of Europe and a clear path to Ukraine’s Nato membership. He insisted that Russia had lost all legitimacy, but said if the coming Ukraine offensive did not meet its military objectives there would have to be an assessment of the nature of future European support for Ukraine. At the same time he insisted that Ukraine was defending not just its own borders, but those of Europe. He also called for continuity in US policy towards Ukraine, but said the EU by strengthening its own defences had to prepare for the possibility that a Republican administration might be elected. In the frankest remarks yet by a European leader about the need to negotiate with Putin, Macron said that “if in a few months to come we have a window for negotiations, the question will be arbitrage between a trial and a negotiation, and you have to negotiate with the leaders you have de facto, and I think negotiations will be a priority … You can put yourself in a position where you say: ‘I want you to go jail but you are the only one I can negotiate with’.” He said that in the meantime evidence against Russia and its leaders should be assembled. Pressing his case for greater European defence spending and coordination, he said “our security and stability should not be delegated and left at the discretion of US voters”. Referring back to his claim three years ago that Nato was in the throes of “brain death”, he said Putin’s invasion of Ukraine had been a wake-up call to which Nato had responded well. But he pointed out that some Nato members – without directly mentioning Turkey – were not imposing sanctions on Russia. He acknowledged that in the past western Europe had not been sensitive to the requests of the east. “Some said you had missed an opportunity to stay quiet. I think we also lost an opportunity to listen to you. This time is over,” Macron said, to applause in the audience. He was alluding to a remark in 2003 by former French president Jacques Chirac, who said eastern European nations which sided with the US and Britain in their decision to invade Iraq that year, opposed by some major western allies including France and Germany, had missed a “good opportunity to stay quiet”. Referring to the division of Europe enforced in the east in the wake of the second world war, Macron said Europe must not allow eastern Europe to be kidnapped by Russia a second time, adding that the enforced estrangement had weakened the whole European family. Macron predicted that the coming Nato summit in Vilnius in July would not be able to reach a consensus on Ukraine’s future membership of Nato, but said “we need to build something between security guarantees provided to Israel and full-fledged Nato membership. We need something tangible, clear and concrete. We need a path to membership”. He added that Ukraine must be given sufficient means to stop further aggression and “we must be able to guarantee they are tangible and sustainable”, because it was protecting Europe. Each country, he said, should have a right to pick its allies. Russia’s invasion had been a geopolitical failure that had aggravated mistrust all its neighbours. “There is no space in Europe any more for imperialistic delirium,” he said. But he also made an appeal to central and eastern European countries not to see greater European defence cooperation, spending and partnerships as a way of reducing Nato’s influence, insisting a strong European pillar in Nato was of benefit to everyone.