Ukraine covers a land mass of some 600,000 square kilometers (about 230,600 square miles). But Moscow considers Ukraine as 20% smaller, given that it views much of eastern Ukraine as Russian territory.

Ahead of the meeting of US President Donald Trump and his Russian counterpart Vladimir Putin in Alaska, Trump said that he wanted to arrange a "land swap" between Russia and Ukraine.

This is a misnomer, however, as Ukraine does not currently control any Russian territory which it could exchange. Its counteroffensive into Russia's Kursk region, which began in August 2024, is largely over. Ukraine, therefore, has no bargaining chip that would allow it to engage in a land exchange. That's why Ukraine and its allies fear Trump could be aiming for Ukraine to cede territory to Russia.

On Monday, Trump is set to receive Ukrainian President Volodymyr Zelenskyy and several top European leaders in Washington to further discuss the issue. 

On Sunday, Trump had already made clear on his Truth Social platform that he only partly supports Kyiv's position. "President Zelenskyy of Ukraine can end the war with Russia almost immediately, if he wants to, or he can continue to fight," he wrote, adding: "No going into NATO by Ukraine. […] Some things never change!!!"

Thus, he made it clear that he considers both the return of the annexed territory of Crimea to Ukraine to be out of the question, as well as Ukraine joining NATO.

According to various international media outlets, Trump and Putin are thought to have agreed at their meeting in Alaska that Ukraine will have to cede the regions of Donetsk and Luhansk to Russia in their entirety. Zelenskyy has so far rejected such an outcome. His European allies have called for a ceasefire along the existing frontline.

Ukrainian territories under Russian control

Russia has focused on gaining control over eastern Ukraine in recent years. After the Euromaidan revolution led to the overthrow of Ukraine's pro-Russian government in 2014, Russian troops occupied the Crimean Peninsula in March 2014 in violation of international law.

On March 18, Russia officially annexed the territory after a sham referendum. Russian fighters then destabilized Donetsk and Luhansk, Ukraine's two easternmost regions. Together, these two regions make up Donbas — the Donets River basin, which flows into the Don River in Russia.

On February 21, 2022, Russia recognized two self-declared pro-Russian "People's Republics" in Ukraine as independent states. Three days later, Moscow launched its large-scale invasion of Ukraine. Ukraine was largely able to repel Russian forces invading from the north during the first months of the war. Yet Russia managed to conquer Ukrainian areas in the east through sheer military might. In addition to about two-thirds of Donetsk and and nearly all of Luhansk, Russia has also taken control over large parts of the Zaporizhzhia and Kherson regions in the southeast, though it does not fully control them.

In September 2022, Russia held further sham referendums in all four regions intended to demonstrate the population's supposed desire to join the Russian Federation. A recent Council of Europe report, however, said civilians face violence and coercion in the regions. The report said those who refuse to become Russian citizens are denied access to social services, education and health care.

Why does Donbas matter?

These areas are of geopolitical significance to Russia. The Donbas has coal and ore deposits, making it an important center for the steel and chemical industry. Rare earth deposits, which are also believed to be present here, will likely continue playing a big role in the future, as they are essential for the production of smart technology and renewable energy. The eastern regions also form a land bridge to Crimea, with Ukraine currently cut off from the Sea of Azov.

The Donbas region, which has seen fighting since 2014, has gained military significance for Ukraine. This is where Ukraine has built a "fortress belt," which is currently the most important defensive line in the region against Russian forces. Although Russia controls large parts of Donbas, it has not yet been able to breach this defensive structure.

Recent talks between the US and Russia have reportedly focused on territorial concessions, with Russia demanding full control over Donetsk and Luhansk in exchange for the return of Kherson and Zaporizhzhia. Yet a recent analysis by the US Institute for the Study of War has warned that giving Russia control of Donetsk would "force Ukraine to abandon its 'fortress belt' […] with no guarantee that fighting will not resume."

What the constitutions say

After holding the sham referendums, Russia amended its constitution to declare the annexed Ukrainian territories part of its own territory. Undoing this step would be fraught with legal and political hurdles and would likely be seen as a defeat by the Russian population.

The Ukrainian government, meanwhile, cannot agree to ceding Ukrainian territory. President Volodymyr Zelenskyy has repeatedly cited Article 133 of the Ukrainian constitution, which explicitly lists all regions of the country, including those in the east and south currently occupied by Russia. The constitution contains a separate section on Crimea, granting it partial autonomy.

Article 2 of the constitution rules out any renunciation of territory. It states that "the territory of Ukraine within its present border is indivisible and inviolable." Territorial changes can only be approved by a nationwide referendum. Constitutional amendments are only permissible, however, once Ukraine suspends martial law.

The Russian and Ukrainian constitutions are, therefore, at odds with each other with regard to Ukraine's eastern regions. Yet, under international law the situation is clear, with lawyers agreeing that Russia's invasion of Ukraine and all sham referendums are illegal.

How NATO fits in the picture

NATO Secretary-General Mark Rutte recently caused a stir when he told US broadcaster ABC that a future deal could acknowledge that "Russia is controlling de facto, factually some of the territory of Ukraine." Would this mean NATO accepting the surrender of Ukrainian territory and thus the redrawing of borders by brute force in its immediate neighborhood?

Rutte said the West "can never accept that in a legal sense," and that only de facto recognition was acceptable. He then drew on the example of US embassies in the Baltic states between 1940 and 1991, when Estonia, Latvia and Lithuania were under Soviet occupation. At the time, the US only accepted de facto Soviet control, while still maintaining diplomatic ties to those opposed to the Soviet occupation.

This article was originally written in German. It was updated on August 18, 2025, in view of recent developments.