The White House went into damage-control mode after General Mark Milley, the chairman of the Joint Chiefs of Staff, suggested that there is no military solution to the Russia-Ukraine conflict and diplomacy is needed to end it: the official US position is that Ukraine itself should set the terms of the peace and decide when, if ever, it's ready to talk. Yet after Tuesday's incident with two missiles landing in Polish territory after a massive Russian strike on Ukrainian power stations, it should be clear why Milley appeared to swim against the US policy tide.

The danger of accidental escalation, or World War III, of a nuclear exchange is ever present while large-scale military action continues in Ukraine. Even if the projectiles that hit Poland were fired by the Ukrainian missile defence and Poland and its Nato allies treat the strike as an accident, there's no guarantee the next alarm won't lead to a need for Nato to get fully involved. That threat trumps — at least from a US perspective — the rest of the fallout from the war, such as the influx of refugees to the European Union, the depletion of European stocks of weapons and ammunition or the energy price hikes. In many ways, the US even profits from the conflict as its defence industry receives more orders, its energy exports become indispensable and its status as the Western world's security pillar is consolidated — but only until it finds itself in an escalation spiral.

That makes it necessary to look beyond the strictly moral stance, which requires that Ukraine be allowed to determine its own future and helped to remain independent and intact. Even though Russia has suffered a string of humiliating defeats, and even if some Ukraine optimists, such as retired US General Ben Hodges, are right that Ukrainians will be well positioned by January to start retaking Crimea, Ukraine is still far from its goal of recovering all the territories that belonged to it prior to 2014. It's impossible to predict what might happen as it pursues this goal into 2023 and perhaps beyond. That's why Milley called on the sides to reach a “mutual recognition” that an end to the war — meaning a quick enough end — is “maybe not achievable by military means“.

It's important, therefore, to think through the ways in which the war can — and cannot — be ended in the near future. Here's my take on the possible scenarios:

1. A swift Ukrainian military victory. It's possible, while unlikely: the Russian surrender of Kherson in the south allows Ukrainians to move combat-hardened troops elsewhere, attack Melitopol and then Mariupol, cut off Russia's "land bridge" to Crimea and make short work of the demoralised Russian units in the east and in Crimea itself. Ukrainians, however, will not go on to take Moscow — they don't have the military power to invade vast Russian territory and they'll likely get no Western help to pursue an invasion. That means the conflict will not be resolved.

After Iran beat back Saddam Hussein's Iraq in its first war of conquest, the deadly conflict resumed several times as Saddam wouldn't give up; peace only came eight years later. By itself, Ukraine's success in retaking Russian-conquered territory is not a lasting solution while Russia's imperialist ambitions persist. Even if Ukraine's victory is sealed with some kind of peace deal, Russia will not honour it — just as neither side honoured the Minsk agreements of 2014 and 2015.

2. The end of the Putin regime. Ukrainian president Volodymyr Zelensky's publicly expressed stance is that he will only negotiate with Putin's successor. It's a long-shot bet but not entirely groundless. The recent mass mobilisation undermined Putin's popularity, and the military defeats have driven even the most pro-war Russians — the ultranationalists — to blame him for the humiliations.

"Absolute power has a reverse side," philosopher Alexander Dugin wrote in a blog post. "Full power given success — but also full responsibility for failure."

But, for one thing, Putin isn't yet so weak that the benefits of trying to overthrow him outweigh the risks. He's still in control of the powerful repressive machine he's built, and both the military and various "freelancers" engaged in the war on Russia's side obey him. And for another thing, if he ever becomes weak enough, likely after more defeats, some kind of democratic revolution is less likely than a takeover by an equally or more hawkish personality or group. No group of Russians remaining in the country, and most certainly no émigré organisation, has the will, determination and broad support required for a successful uprising or even the ability to execute a coup. So even if Putin falls — or dies a natural death — the conflict, quite likely, will not be over.

3. A backroom deal. For all the talk of a diplomatic effort, for all the rumours and speculation that Russia is ready to talk peace if it's allowed to hang on to a minimum of territorial gains (see the Elon Musk tweeted "proposal"), for all the fears harboured by the Russian nationalists that the Kremlin will make a deal behind their backs, this is the least likely of all scenarios. A deal whereby Russia keeps any Ukrainian territory at all is a political impossibility for any Ukrainian Government.

Even if Western support dries up to a trickle, Zelensky will be forced to fight on because that's what the majority of Ukrainians insist on; that's why he stood and fought before much of the aid arrived. And even if Zelensky, or some successor, weakens and does a deal, it will not stand for long. The Finns, defeated by the Soviets in the Winter War of 1939-1940, came back with the Nazi invading force in 1941, retook the lost territory and only stopped some 20 miles from the centre of Leningrad.

4. A Russian military victory. Perhaps counter-intuitively, it would actually end the conflict: it would mean either the inclusion of the entire eastern and southern Ukraine in Russia or the installation of a puppet government in Kyiv — in other words, the subjugation or disappearance of Ukraine as an independent actor. Of course, Western sanctions pressure on Russia would persist, and Russia would have Ukrainian guerilla action to contend with, but the Soviet Union has previously succeeded in suppressing it and making Ukraine, even its Western part, relatively docile.

Given the events of the past few months, however, this scenario is highly unlikely, and in the short term simply impossible. The Russian military doesn't have what it takes to defeat Ukrainians on the battlefield — at least not now. It has lost the initiative and, en masse, it never had the necessary motivation. It needs to rearm, restaff and retrain, all extremely difficult tasks during an ongoing conflict. The chance at shock and awe was wasted back in February and early March, reality has set in, and, after decades of corruption and systemic rot, it's not a pretty reality for the Russian army.

5. A strategic defeat of Russia by the West. Some Western policy experts have advocated for it without saying what it would require. It's not prudent to say the quiet part out loud, but a strategic defeat would mean an occupation, de-Putinization and denazification of Russia — the fate of Germany and Japan after the Second World War.

It can only be achieved if Nato gets drawn into a conventional conflict and decisively defeats the Russian military, while nuclear weapons somehow remain unused. It's not impossible despite Putin's nuclear threats, designed to avoid this specific scenario. The Russian leadership is not necessarily crazy enough to let the world go down in flames to prevent a decisive defeat.

But no Western political leader, certainly not Joe Biden, appears to have the appetite for extreme risk required to put Nato boots on the ground and invade Russia. Indeed, there appears to be appetite for ending the war by any other means just to avoid having to make this decision.

Barring a divine intervention, there appears to be no realistic way to end the conflict soon. And this means it will drag out until divine intervention is no longer the only solution. As it drags out, more incidents like the Polish one will threaten to upend all the wargaming and editorialising. And Ukrainians and Russians will keep dying by the thousands.

Leonid Bershidsky, formerly Bloomberg Opinion's Europe columnist, is a member of the Bloomberg News Automation Team.