Ukraine’s battlefield success also raises the question of how far Kyiv intends to go. President Volodymyr Zelensky seems intent on driving Russian troops from all of Ukraine, including those territories Russia occupied in 2014, Crimea and a portion of the Donbas. “We will return there,” Mr. Zelensky recently said about Crimea. “I don’t know when exactly. But we have plans, and we will return there, because this is our land and our people.” Mr. Zelensky has also forsworn any diplomacy with Russia as long as Mr. Putin is in power.
Ukraine’s war aims are morally and legally warranted, but they may not be prudent. In response to recent Ukrainian gains, Mr. Putin has doubled down, not backed down. When he announced the annexation of an additional chunk of eastern Ukraine on Sept. 30, he insisted that the people living in that region “are becoming our citizens —forever.”
A conflict that had been about the future of Ukraine has become for Mr. Putin an existential struggle for the future of Russia: “The battlefield to which fate and history have called us is the battlefield for our people, for great historical Russia, for future generations,” he declared.
Mr. Putin is raising the stakes and backing himself into a corner. Accordingly, the Kremlin’s resort to a nuclear weapon becomes a realistic option should Russian forces face full expulsion from eastern Ukraine and Crimea. If Mr. Putin crosses the nuclear line, NATO would almost certainly become directly involved in the war, with the potential for nuclear escalation.
Ukraine’s battlefield successes could go too far. If the defense of Ukraine is not worth U.S. boots on the ground, then the return of all of the Donbas and Crimea to Ukrainian control is not worth risking a new world war. Russia has already been dealt a decisive, even if not complete, strategic defeat in Ukraine. Given Ukraine’s battlefield advances, Kyiv and its NATO partners are understandably tempted to try to vanquish Russia and restore Ukraine’s full territorial integrity. But Mr. Putin’s effort to subjugate Ukraine has already failed, and pushing for Russia’s total defeat is an unnecessary gamble.
The United States and its allies also need to be concerned about the rising economic and political threat that a long war poses to Western democracy and solidarity. The trans-Atlantic community has so far shown remarkable unity and resolve in supporting Ukraine, but the West’s staying power may be fragile.
The original Cold War occurred when the West was politically healthy, enjoyed widely shared prosperity, and was anchored by ideological centrism. Today, democratic societies on both sides of the Atlantic confront political polarization, economic duress and ideological extremism. Despite the return of military rivalry with Russia and intensifying competition with China, the United States and its democratic allies in Europe remain imperiled by illiberal populism and angry and divided electorates.