Ukraine has agreed to a 30-day ceasefire, in large part to patch up its relations with US President Donald Trump’s administration, which unravelled during a February 28 Oval Office confrontation between Trump and Ukrainian President Volodymyr Zelensky. Russia rejected the ceasefire proposal, instead suggesting — but not implementing — a prohibition on attacking energy infrastructure. Both sides also indicated a readiness to accept a ceasefire in the Black Sea, but with Russia linking its support to a relaxation of sanctions, it is far from clear when — or even if — such a limited ceasefire would start, much less what it would encompass.

Such partial steps, if implemented, could be a way-station to something more significant. But it is at least equally possible that these partial steps won’t lead to a comprehensive peace agreement. Russia could prosecute the war even if the Black Sea were not an active theatre.

The biggest question remains US policy. The Trump administration has used a combination of pressure and incentives to persuade the two sides to stop fighting. But its approach has been skewed towards offering benefits to Russia while bringing heavy pressure to bear on Ukraine.

To be clear, it is appropriate to offer Russia certain incentives. This could include a willingness to resume high-level contacts and restaff embassies, support for limited relaxation of sanctions if specified conditions are met, and to allow Russia to keep its long-term objectives for Ukraine on the table.

What is not acceptable is to embrace flawed Russian positions, such as its claims to Crimea, Donetsk, Luhansk, Kherson and/or Zaporizhzhia based on the results of illegal referenda conducted by Russian occupation forces. It is one thing for Trump’s envoy to the Kremlin, the property-developer-turned-novice-diplomat Steve Witkoff, to characterise Russia’s stance and quite another for him to adopt it as his own.

More broadly, there is no good reason to introduce final-status considerations at this point. The goal for now should be an open-ended ceasefire agreement, not a permanent peace treaty. In this instance, excessive ambition is likely to be the enemy of the possible.

To achieve a cessation of hostilities, the agreement ought to be as clean and simple as possible. Only two elements are essential for a viable ceasefire: a cessation of all hostilities, and a separation of forces, ideally with a peacekeeping contingent between them.

Everything else, including the disposition of territory and populations, should be left for final-status negotiations. For now, both sides should be allowed to arm or agree to security arrangements with third parties. Nothing should be done to preclude measures that would buttress a ceasefire. Russia should be permitted to retain North Korean troops on its territory; Ukraine could invite forces from European countries.

What is essential is for the US to continue providing military and intelligence support to Ukraine. Such support is the only way to convince Vladimir Putin that further stalling is not in his interest, and is essential to Ukraine’s ability to deter renewed Russian aggression even if there is a ceasefire agreement. But it need not be unlimited: such US assistance has totalled around $40 billion a year for three years — a level that is likely to suffice for the foreseeable future.

The goal should be to give Ukraine what it needs to deter and defend against Russian aggression, not to liberate its lands. To assert, as Witkoff did, that there is no reason to worry about renewed Russian aggression is not serious. After all, the current war is Russia’s second invasion of Ukraine since 2014, when it illegally annexed Crimea. Given Putin’s intentions, what matters are capabilities.

Matters could come to a head by summer, when the pipeline of congressionally approved arms for Ukraine runs out. The Trump administration will have to decide — if it has not already done so — on the connection between the security relationship with Ukraine and US diplomacy.

As we attempt to discern what the administration will choose to do, the February 2020 deal that the first Trump administration signed with the Taliban should give us pause. The agreement was negotiated over the head of America’s Afghan partners through direct talks with the Taliban, paving the way for the Taliban’s swift takeover of Afghanistan a year and a half later. One can only hope that the price Joe Biden paid, both domestically and internationally, for implementing Trump’s deal would lead Trump to think twice before abandoning Ukraine to a similar fate.

Trump should also keep in mind that abandoning Ukraine would not bring peace. Zelensky, who is more popular than ever at home — thanks in no small part to the infamous Oval Office meeting — would likely opt for no ceasefire or peace treaty rather than one that compromised Ukraine’s core interests. It could fight on in one form or another for years using domestically produced arms and weapons imported from Europe and Asia — and, free of US restrictions as a condition of aid, it might even be tempted to act more aggressively in its choice of targets within Russia.

At the same time, Russia would most likely view US separation from Ukraine as an opportunity to press or even escalate militarily. Far from bringing peace, a US military cutoff of Ukraine could actually bring about an escalation in the fighting.

The stakes are high, and not just for Ukraine. What plays out with Russia will have a significant effect on the future of Europe, on whether China uses force against Taiwan, or North Korea against South Korea, and on how the US is perceived both by its friends and enemies around the world.