Ukraine's agreement prompted the resumption of US intelligence sharing and military aid, which may well have been Kyiv's primary aim. Mr Trump would like to take the credit - and perhaps aspires to a Nobel prize - for a peace deal. Mr Trump, who was hosting Nato's secretary general, Mark Rutte, described the Russian president's remarks as "very promising" albeit not "complete". Even if he outsources the patience and focus required to reach an agreement, it is clear that he has no interest in the injustice or illegality of the invasion, that his sympathies lie with Mr Putin, and that he bears a deep grudge against Mr Zelenskyy.
Fundamentally, Moscow can be more confident of its position than it was even a month ago. The west has been shown to be fundamentally divided and therefore weakened. On the battlefield, Russia also believes itself to have the upper hand, however painful its progress has been. It does not want to give Ukraine the chance to regroup. Speaking ahead of a meeting with the US envoy, Steve Witkoff, Mr Putin was too canny to dismiss Mr Trump's plans outright. There will always be ways to defer a deal, or sabotage it later.
The bigger issue is not its short-term hope of taking more territory, but its long-term, maximalist ambition to control Ukraine. Mr Putin remarked that a ceasefire should "remove the root causes of this crisis": among other things, he wants its demilitarisation and assurances that it won't join Nato. ("They discuss Nato, and being in Nato, and everybody knows what the answer to that is," Mr Trump remarked.) Mr Putin certainly does not want troops from Nato countries there. But without them, Ukraine has no reason to believe that a halt on Russia's part would be any more than a tactical measure. This is why, as Sir Keir Starmer said on Thursday, "It has to be a peace where the deal is defended."
Provisional halts in combat can lead to lasting peace; no treaty was signed to end the Korean war. And Mr Putin could yet see genuine advantages to a diplomatic route, especially if it involves early relaxation of sanctions. Russia is expert at interference operations and would surely see opportunities in a post-war Ukraine, with the option to return to warfare always available further down the track.
The zigzags of recent days may materially affect the outcome of this conflict. The halting of aid and intelligence facilitated Russia taking back territory that Ukraine had seized in Kursk. Its resumption will allow Ukraine to fight better for longer. But the overall trajectory is still clear, and it leads away from US support for Ukraine and Europe. It is not unthinkable that Mr Trump might attempt to punish European nations for supplying arms to Kyiv in due course. Whether he is willing to exert real pressure on Mr Putin will shortly become clear. But neither Ukraine nor its friends can expect it.