In his quest for an agreement to stop the war in Ukraine, U.S. President Donald Trump began with the easy part: putting pressure on Ukrainian President Volodymyr Zelensky, who is dependent on U.S. military support. Now it’s time to face the hard part: putting pressure on Russian President Vladimir Putin.

Ukraine has agreed to a thirty-day ceasefire without preconditions and in full—not just in the air and at sea, as it had previously proposed. In return, it received what it had been getting until just a few days earlier without any ceasefire: a resumption of intelligence sharing and previously approved U.S. aid. Now, as U.S. Secretary of State Marco Rubio put it, “the ball is in Russia’s court.”

Ahead of U.S. special envoy Steve Witkoff’s arrival in Moscow on March 13, Russian presidential aide Yury Ushakov appeared to reject the ceasefire proposal on the grounds that it would merely provide Ukraine with a temporary respite, enabling it to rally its forces. Indeed, Moscow is unlikely to respond with a simple and honest cessation of hostilities at a time when the Russian army has begun recapturing territory in Russia’s Kursk region that had been seized by Ukrainian troops. It could try to persuade the Americans to give it time to complete the Kursk operation, or to exclude it from the ceasefire agreement, though even Trump would likely have a hard time accepting that: it would imply that Ukraine is a legitimate battlefield while Russia is not. Another option for Moscow is to simply drag out its response in the hope of quickly completing the recapture of the region.

But what about the overall war? After initial setbacks and uncertainty, Russia is now increasing its advantage on the battlefield, and is ahead of Ukraine and its allies in terms of weapons production. In Russia, a consensus has emerged in the militaristic segment of the elite and society that Ukraine cannot hold out for much longer. Stopping the campaign now will be perceived as giving up an inevitable victory. Putin himself has said repeatedly—including recently—that Russia was only a few months short of victory in World War I when the Bolshevik government withdrew the country from the war on disastrous terms. The main thing now, therefore, is to avoid repeating that mistake and to see it through to the end.

The Kremlin already perceives the resumption of intelligence sharing and military aid to Ukraine as an unfriendly gesture by Washington and an attempt at intimidation, and Putin tries never to act under pressure. Restoring assistance to Ukraine is perceived by Moscow almost as a betrayal by Trump: he may only have been in power for a few weeks, but the Kremlin had already gotten used to having a kind of unwritten alliance with the new U.S. administration.

Then there are economic and domestic political factors for Moscow to take into account. Russia has boasted extensively of its economic growth under sanctions, presenting it as a kind of passive economic miracle: a story of normal life and industrial growth under unprecedented economic pressure that will go down in history. Since that growth stems in part from putting Russia’s economy on a wartime footing, it inevitably gives rise to fears that if the war ends, so will that growth—with alternative sources of growth as yet unidentified.

The war has also become the raison d’être for the jaded Russian leader, as well as a social elevator and a source of self-esteem for a significant number of middle-aged and older Russian men. In the last three years, Putin has gotten used to poring over maps, handing out awards, posing with soldiers dressed in military fatigues and adorned with medals and epaulettes, comforting widows and orphans, visiting the wounded, branding people traitors, and casually threatening global capitals with weapons systems. An end to hostilities would deprive Putin of his life’s mission.

Such a loss could only be mitigated by securing a certain set of inflated Russian demands. Unlike Ukraine, Russia has already begun to put forward its demands at the earliest stage of talks on its participation in the ceasefire—not least to emphasize the glaring inequality between the negotiating parties. In addition, Russia is effectively being asked to sign up to a ceasefire agreed upon between the United States and Ukraine without Moscow’s involvement. Even if the conditions were acceptable to it, it would be a matter of honor for Russian diplomats to put forward their own conditions.

The demands already voiced are nothing new: territorial concessions from Ukraine, a permanently neutral status, a change of president through elections to which all candidates and all media— including Russian ones—must be admitted, and the absence of Western troops and military guarantees for Ukraine.

Trump must face a fateful choice. He can try to put pressure on Russia, since it can no longer be said that it is Ukraine that is being intransigent and impeding his victory as a peacemaker. Or, faced with the fact that he has no leverage over Putin for achieving a quick result, he can once again show solidarity with the Russian leader and start promoting Putin’s list of demands as a joint one.

It will not be easy for Putin to simply reject Trump’s ceasefire proposal outright, since that would dash the U.S. leader’s peacemaker ambitions and in some ways make him seem like Zelensky, who “does not want peace.” What Moscow can do, however, is to make it seem like it will agree eventually while dragging out the negotiations.

Russia could conduct protracted negotiations on the terms of the ceasefire, while varying the intensity of its assault on the battlefield in the meantime. If the fighting simmers down, such a state of affairs may suit both Trump and Putin. The former can still proclaim his peacekeeping endeavors have been a success, while the Kremlin will not formally be bound by any obligations and can wait for an opportune moment to continue the war or insert itself into Ukraine’s election process, threatening to ramp up the war again if the results are not to its liking.

Trump has few options to counter either a Russian rejection or protracted feigned compliance. The most effective method will be the carrot rather than the stick: the temptation of a major deal. Before Trump’s election victory, Ukraine was the main front and focal point of Russia’s efforts to rewrite the outcome of the Cold War. Trump has the power to turn Ukraine into a concrete example of a much broader reversal of that outcome. But whether or not he is willing to pay that price for peace between Russia and Ukraine remains to be seen.