I was a UN mediator – Trump’s strategy on Ukraine is smarter than you think

Marc Weller is Professor in the Department of Politics and International Studies in the University of Cambridge, is a former UN Senior Mediation Expert and has served as Senior Adviser in dozens of international peace negotiations.

He is the co-editor of International Peace Settlements, Cambridge University Press, 2021.

This article first appeared in THE iPAPER on 6 August 2025

I was a UN mediator – Trump’s strategy on Ukraine is smarter than you think

Trump's Russia strategy is a textbook exercise in negotiating theory, says Professor Marc Weller, a former Senior UN Mediation expert who has advised on dozens of peace negotiations.

“War is only a cowardly escape from the problems of peace,” said Thomas Mann, Germany’s leading writer of the 20th century. Indeed, moving from war to peace is a complex art that requires courage and sacrifice. 

Donald Trump’s determination to make peace in Ukraine, first within a day, then in 100 days, and now without a definite timetable, or perhaps after all by the end of this week, has caused considerable confusion and derision in the West. Many complain of a naïve reliance on Russia’s will to peace matched by unfair pressure against Kyiv, the victim of aggression. In addition, there are those rapid and unpredictable apparent changes in the US position. But suspend your disbelief for a moment. Believe it or not, US action on Ukraine has so far been a textbook exercise in negotiating theory. However, that toolbox is slowly being exhausted, with Russia being unmasked as the remaining obstacle to peace. Steve Witkoff’s mission to Moscow this week may be last moment in a good while to move towards an actual peace settlement. 

There already was a strategy for mediation on Ukraine 

To start with, there actually was a plan, or what the experts call a conflict analysis, leading to a mediation strategy. 

In April 2024, a long way before the change in the US Administration, Retired Lt General Keith Kellogg, Chief of Staff of the National Security Council in the first Trump administration, and former senior CIA analyst Fred Fleitz published an analysis of the war. They concluded that no side would be able to fully achieve its military objectives through force. The sides were persuaded that, if only they held their nerve and kept fighting, they might still achieve their key aim, if not tomorrow, then the day after.   

Ukraine refused to accept that it had effectively lost nearly a quarter of its territory. Russia wanted to complete its conquest of the four additional provinces it had captured, in addition to Crimea, its earlier trophy of 2014, and demanded international recognition of their purported annexation, along with rendering Ukraine a neutral state. 

The only way to end the slaughter would be for the US to devise a settlement that would impose equal sacrifices on both and use American power to force them to accept it.  

The plan was that the US would offer a realistic and balanced peace settlement, threatening whichever sides that would not accept it with major negative consequences. For Moscow, this would be further isolation and still tougher sanctions. For Kyiv, this would mean a withdrawal of the support lavished upon Ukraine under fire, including supplies of missiles, munitions and intelligence.

From Key Ukrainian Ally to Neutral Mediator 

Step one occurred when Trump started to romance Russia at the start of his administration. Having given the bulk of crucial military and intelligence aid to Ukraine during the Biden years, Kellogg insisted that the US would now need to place itself as an ‘objective interlocutor.’   

Ironically, this meant that Trump gave in when Russia rejected Kellogg as principal mediator in view of his argument in favour of strong punishment for the side that would refuse to play the US game. Instead, he was relegated to the role of managing relations with Ukraine, with Steve Witkoff emerging instead as principal negotiator along with Secretary of State Marco Rubio.  

Initial mood music was positive on the Russian side. A first long telephone call between Trump and Vladimir Putin in February was considered “highly productive,” leading to fears on the part of Ukraine and the European allies that a rapid deal would be concocted between both leaders, effectively leaving out Ukraine. 

But a meeting with a senior Russian delegation led by the indomitable Sergey Lavrov, veteran Foreign Minister, suggested Moscow would not easily depart from its maximalist position – while still remaining keen to show a willingness to engage as cover for further conquests on the ground. 

In truth, at the time neither side was actually willing to engage in serious negotiations. In negotiating theory, this means that the conflict was in fact not “ripe for resolution”, rendering mediation attempts futile.

Cutting Zelensky down to Size 

There are two possible responses to such a situation. Normally, it means that a mediator waits for things to change. Or in case of a powerful interlocutor, the mediator can herself effect the necessary change. This seemed possible, at least in the case of Ukraine. 

The second step was to bring Ukraine into line. The calamity in the Oval Officeof February occurred when Zelensky failed to follow the script US officials had practised with him, instead challenging Trump by arguing in favour of US security guarantees as the price for signing the controversial minerals agreement and acceptance of a ceasefire. 

The administration tried to persuade Zelensky that the deal would give the US a long-term strategic interest in Ukraine’s survival – a security guarantee of sorts. However, while in principle willing to sign, Zelensky went off script. He saw the initial welcome meeting as an opportunity to raise his key argument in favour or actual, hard military security guarantees for Ukraine, should the US manage to bring a settlement about. Ukraine was and remains persuaded that any cease-fire or peace deal will only amount to a break in Russia’s attempt to extinguish it as an independent nation.

The US then rather brutally demonstrated that Zelensky “does not hold any cards” by withdrawing its love, missiles and intelligence support to show that Ukraine could only survive if it acted in accordance with Washington’s demands.  

Good Cop – Bad Cop

It took the calming hand of UK Prime Minister Sir Keir Starmer, and even tea with King Charles, to bring Zelensky back in line. Zelensky offered something like an apology to Trump and a much improved and more balanced version of the minerals agreement was duly signed. Zelensky even accepted the US demand for an immediate, 30-day cease-fire, despite his conviction that Ukraine might still roll back the slow but steady Russian advance.  

This placed the UK in the role of good cop in relation to Ukraine, offering strong political and military support while assuaging the giant in the White House. The US assumed the position of bad cop in forcing its terms – or sense of realism – upon Zelensky. 

Having set Ukraine on the path to a possible agreement, the question was how to turn Russia. The White House correctly calculated that Putin would be much more difficult to press into concessions. Sanctions had not made much of an impression, given the fact that only the West was participating. Neither had the threat of diplomatic isolation. Indeed, threats might make a settlement impossible, as Putin might be loath publicly to appear to cave in to US pressure. Hence, Trump continued in his attempts to draw the Kremlin in rather than threatening him, offering the prospect of global rehabilitation, removal of sanctions and deepened economic co-operation.  

So in relation to Russia, the situation was reversed. The US as the good cop still tried soft persuasion in favour of a ceasefire followed by a political deal, while the UK as bad cop led the European coalition arguing for tougher action to force Moscow to stop fighting. Together with president of France Emmanuel Macron, and lately Germany’s newly installed Chancellor Friedrich Merz, the British PM started to array Ukraine’s European powers in support of deploying a somewhat illusory peace force to stabilise a ceasefire.   

But Putin insisted that there could be no ceasefire until there was a political settlement that would ratify his conquest, neutralise Ukraine, and reduce its army and weaponry. His counter-move, intended to show pretend flexibility, consisted of an ineffectual “Easter truce” and a similarly ineffectual agreement for both sides to stop targeting each other’s energy infrastructure. 

Creating the decisive moment

It was at this point that the US attempted to generate a decisive moment in the negotiations. Engineering such a point of decision is meant to force a recalcitrant side to opt either for more constructive engagement towards peace, or to be blamed for the breakdown in the peace process and face further international sanctions.  

The US response was the most daring thus far. The mediation issued a set of principles to the sides that could fit onto the back of an envelope. This mini framework for a substantive settlement was quite brilliantly conceived, offering each side what, at a minimum, they would need to bring home in a peace settlement that their domestic constituencies might just about accept. In this way, it was thought, the deadlock over “ceasefire first” or “political settlement first”, might be overcome. There would be a ceasefire, but in an environment where the base points for a settlement had been established. 

These principles were, in fact, quite cunningly drafted. They included de facto but not de jure acceptance of Russia’s conquest, but only to the point actually achieved on the ground at that moment. The US alone would defy international law and offer to grant de jure recognition to the incorporation of Crimea, occupied and supposedly annexed by Russia since 2014, at least partially fulfilling a key Russian demand. Sanctions against Russia would be progressively lifted and replaced with enhanced economic cooperation with the US. 

The US was much criticised for “giving away” key concessions on behalf of Ukraine, including no Nato membership and de facto acceptance of the territorial outcome of the fighting. Indeed, there was a significant risk that Moscow would bank these concessions, and then start negotiating for more.   

To counter that risk, the US asserted that this was the “final offer” and no changes to the framework would be contemplated. This would mean that Russia would be clearly identified as the obstructive party, laying itself open to the enhanced sanctions Kellogg had anticipated a year before, unless it accepted a cease-fire and negotiations on the basis of the carefully balanced list of principles. 

The critical moment lost 

But the game was spoilt by Ukraine, which sent Trump a version of his principles that was modified in a few key points. For instance, the US was assigned the role of providing a security guarantee on part with Nato’s Article 5on collective defence. 

This was essentially the second time that Ukraine failed to follow the US line. And it was a critical mistake. In fact, Kiev could have lived with the US principles, perhaps seeking to advance its position in the negotiations that would have followed about fleshing them out. 

But this Ukrainian misstep allowed Putin to evade the moment of decision constructed by the White House by appearing to render the non-negotiable, final list of US points negotiable after all.  Moscow took the cue and offered direct negotiations with Ukraine at a fairly low level and excluding the US. Unsurprisingly, these talks held in Istanbul yielded no results beyond some welcome prisoner exchanges. 

Change of heart in Washington?

In essence, this outcome brings us back to where we were six months ago, at the outset of the Trump mission to make peace. The sides have now formally stated their positions. These positions are still diametrically opposed and incompatible. Hence, what negotiations analysts call a “Zone of Possible Agreement” is missing. The conflict is still not ripe for resolution. The various moves made by the Trump team have not managed to change that situation.   

On the other hand, in following the negotiator’s handbook, the US has achieved more than is evident at first sight. There now exists a blueprint in miniature, demonstrating that a settlement could be possible. 

While Ukraine is reserving its position in its direct discussions with Moscow, it now seems likely that Ukraine would in the end accept a deal based on the US “final” proposal, even if unenthusiastically. This implies painful concessions and sacrifices imposed by the sad reality of the situation and would have been unlikely some months ago. 

The European partners have now understood that they would be principally left to address the issues of security guarantees for Ukraine on their own, with only limited US involvement. They have started to engage in real planning accordingly, whether it is for sustaining Ukraine in the war, for supporting a cease-fire, or assuring Ukrainian security after a settlement. 

In this context, it is now clear that the issue of security guarantees for Ukraine will likely need to be separated from that of cease-fire monitoring. The former task would fall to a coalition of the willing formally allied with Ukraine but exclude a significant military presence in Ukraine. The latter would need to be fulfilled by states also acceptable to Russia, probably acting under a soft UN peace observation mandate on the ground. 

The US has gone very far in placing itself as a more “objective interlocutor” vis-à-vis Russia. The US calculation that Putin is unlikely to buckle to the kind of pressure the West can muster, after having successfully resisted for over three years, suggested that alternative, cooperative approach. This may not have been realistic, given the deeply rooted, neo imperial nature of the war aims of Putin concerning Ukraine, and his wish to reassert his country as a great power at the expense of Nato once more. But it was worth the try, given the absence of viable alternatives. 

Washington has now given the Kremlin ample opportunity to exhibit interest in a settlement. Putin in turn has now pretty much exhausted his repertoire of manoeuvres to avoid engaging seriously. Moreover, in continuing the provocative and militarily useless assaults on civilian installations, including hospitals, in the midst of Trump’s personal telephone diplomacy, he has managed to persuade Trump that he is being taken for a ride. He also genuinely resents the human toll exacted by Putin and his forever war.

It is now undeniable that Ukraine, the victim of aggression, is willing to settle, while Russia, the aggressor, is still banking on unqualified victory. This clear outcome opens the way for the application of yet greater pressure against Moscow, also for the previously reluctant White House. 

Of course, the US may instead drop out of the issue if its threat yields no result. However, this would unmask the recent tough stance of the White House as empty bluster, undermining Trump’s credibility in global affairs. 
The US and Europe may now instead be in a position to act jointly to increase the penalties for Russia for drawing out the war, including through third party sanctions against states supporting Russia. Trump’s re-deployment of two nuclear submarines closer to Russia signals that the time for soft games may be over. 

Having exhausted the soft mediator’s options, the present mission to Moscow by Witkoff, two days before the expiry of the deadline set by Trump before the imposition of additional measures against Russia, represents the next step taken from the negotiations textbook. It means changing the negotiating environment by increasing the costs for the recalcitrant side and adding risks for it that are difficult to calculate. In fact, the US deal remains the best and perhaps only way out of the senseless slaughter that will, if continued, not really advance Moscow’s position by very much.