Imagine being told 40 days ago that Ukraine and NATO would eventually be in a position to discuss whether the goal of the Ukrainian military should be total expulsion of Russia from Ukrainian territory. (Minus Crimea, that is.)

But that’s where we are, 40 days later.

Which is not to say that the Ukrainian military certainly could achieve such a goal if it wants to. Nor is it to say that Russian “defeat” requires nothing less than evicting all of its troops from the east. If Ukraine fought Russia to a “draw,” in which the two sides agreed to resume the status quo ante prior to Russia’s invasion, that in itself would be a terrible and chastening humiliation for Moscow.

The debate that seems to be playing out within NATO at the moment is over whether we’ve reached the point where new territorial concessions to Russia in the name of ending the war should be ruled out. Zelensky has ruled them out publicly, but that may be a case of him setting a negotiating baseline. Three weeks ago, if Putin had demanded the Donbas in return for withdrawal elsewhere, all sides might have (grudgingly) agreed to it. Now, after Russia’s embarrassing retreat in the north, Ukraine and its allies seem less inclined to concede anything. Particularly when no one knows how game the Russian military is for a protracted war in the east.

Technically, only Zelensky and his deputies get to decide how long to fight. But because NATO is the arsenal of the Ukrainian military, forcing a ceasefire on Kiev presumably wouldn’t take much more than threatening to turn off the tap of weapons. The U.S. and its partners are talking over the preferred endgame here:

Central European members like Poland and the Baltic states want a total break with Moscow and an effort to bring Russia to its knees, two senior Western officials said. They worry that anything that Russia can present as a victory will do serious damage to European security.

But other nations believe that Russia cannot be easily subdued and that the war’s outcome is likely to be messy — more exhausting cease-fire than resounding victory. Countries like France, Germany and Turkey want to keep contacts with Russia’s president, Vladimir V. Putin, regardless of the allegations of war crimes committed by his troops, the officials said…

Some countries, especially in Central Europe and including Britain, are anxious that any sort of Russian expansion into Ukrainian territory, let alone a Russian victory, would embolden Mr. Putin, undermining overall European security and values such as the adherence to international law, respect for national sovereignty and territorial integrity. They want Russia to be seen as the loser.

The dispute over the intended outcome is also a dispute over what sort of weapons to supply. If the goal is Ukrainian victory then Zelensky should get everything — tanks, long-term artillery, anti-armor Switchblade drones, the works. If the goal is simply wearing Russia out and forcing Moscow to seek a settlement, defensive weapons should do fine. Jens Stoltenberg, the head of NATO, is worried about a long war, saying today that “We have to be realistic and realize that this may last for a long time, for many months or even years.” But is that realistic, given how precarious the readiness of the Russian army seems to be? How long can they plausibly go?

Granted, they’re redeploying units from the north to the east, but so is Ukraine. And those veterans of the north might not be in any shape to fight, warns Ret. Gen. Mark Hertling:

BTW, before we leave breakthrough, Brusilov & his followers say RU must use massive artillery on enemy positions OR use *battlefield tactical nuclear weapons* to create a breakthrough when gaps are found by the RIF.

Again, theoretical…but that scares the crap out of me. 13/

— Mark Hertling (@MarkHertling) April 6, 2022

Russia is looking to break through Ukraine’s lines in the east and proceed to Slovyansk and Izyum, southeast of Kharkiv. If they can link up there with Russia’s remaining forces in the north, they could potentially surround Ukraine’s forces in the Donbas. That would leave Putin in a position of (relative) strength, able to threaten Zelensky with the total loss of those forces unless he concedes Luhansk and Donetsk to Russia. If Russia can’t break through, the situation will turn desperate. They’d be left with a choice between defeat and trying to simply grind down Ukrainian forces until a settlement resembling the pre-war status quo can be reached. Assuming Russia’s forces aren’t ground down first, of course.

Or, I guess, they could always choose door number three, the WMD scenario Hertling worries about. Using a tactical nuclear weapon if Russia is on the brink of a catastrophic defeat would be a textbook example of the “escalate to deescalate” strategy the Russians have promoted over the past decade, in which the enemy is stunned into suing for peace by Moscow’s reckless show of strength.

We’re still a ways away from that, hopefully. Hertling knows what Ukraine will have to do before then in order to force the prospect of a humiliating loss on Putin:

But, UKR must also find ways to be more mobile for this new phase.

First, they'll need very good intelligence about where RU forces are moving.

Then, tanks they've "acquired" from RU and those provided by NATO nations will help. 15/

— Mark Hertling (@MarkHertling) April 6, 2022

UKR must defend their own supply line, interfere with RU C2, logistics, and movement…

…while also conducting other unconventional operations behind RU front lines.

— Mark Hertling (@MarkHertling) April 6, 2022

They have advantages in high morale and shorter supply lines. They also have a momentary advantage in terms of time, with estimates ranging from “several weeks” to a full month before Russia has regrouped following its northern withdrawal and begins to press hard in the east. If NATO opts to go all-in and give the Ukrainians the weapons they want, which is what it seems inclined to do, the prospect of Russian defeat isn’t unthinkable even if it’s not assured.

Whatever happens, NATO’s posture towards Russia has changed for the indefinite future. The current draft of the alliance’s new strategic concept is reportedly “much tougher on Russia, and foresees a longer period of confrontation and expensive deterrence.”

Here’s Hertling on CNN today. Get ready for a war of attrition in the Donbas, he warns. Which bodes ill for the side with the infamously poor logistics.

Retired Lt. Gen. @MarkHertling explains why the Russian military is focusing on the cities of Izyum and Slovyansk in eastern Ukraine and how the war on the ground is changing in the region. pic.twitter.com/NX5dFX9QcC

— CNN (@CNN) April 6, 2022