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The Biden administration's decision to approve Ukraine's use of U.S. weapons to attack targets inside Russia is, as President Biden might say, a big deal. Ukrainians argue that this change will derail the Kremlin's offensive in the Kharkiv region and perhaps even turn the tide of the war. Russian officials and propagandists claim it is a major escalation and have threatened to strike back directly at the United States or its allies.

Both claims are likely to prove hollow. But this decision is nevertheless consequential, if for a different reason: It marks another turn of a tit-for-tat spiral that has continuously raised the risks of a broader war without offering a path to ending this one.

This isn't the first time the United States, under pressure from Ukraine and Western allies, has crossed a threshold previously deemed too escalatory. Past decisions on HIMARS launchers, cluster bombs, long-range munitions, and F-16s were also driven by perceived Russian gains on the battlefield.

Strikes inside Russia using U.S. weapons might slow military operations around Kharkiv, but they will not be a game changer. Russia's Kharkiv push has already gotten bogged down around the city of Vovchansk, which is less than five miles from the Russian border. With strikes on supply lines in Russia proper, the offensive could slow further, but the Russians are likely to adapt, as they have to previous U.S. moves. After all, U.S. weapons are routinely used to hit Russian supply lines and command posts in occupied eastern Ukraine, with Russia nevertheless steadily realizing gains there. And so the grinding, attritional war will continue.

Past evidence also suggests Russia is not going to dramatically escalate just because the United States provides a new weapons system or eases constraints on an existing one. Russia is, relatively speaking, winning the war at the moment, so it is unlikely President Vladimir Putin will take the risk of provoking direct conflict with the United States and its allies. Moscow might well respond, but it is likely to do so in an indirect or asymmetric way, rather than firing a missile into a European capital next week.

The real problem with Biden's decision is that Washington has yet again made a major policy change reactively—in response to Russia's military moves and not as part of a broader strategy to end the war. The Russians will continue to push, and in three or six months the United States could find itself back here again, under a similar Ukrainian and allied pressure campaign, tempted to breach its next threshold to try to reverse the negative trajectory. As Secretary of State Antony Blinken put it, “we'll continue to do what we've been doing, which is, as necessary, adapt and adjust.”

But adaptation and adjustment do not constitute strategy, and reactive escalation absent a strategy is not sound policy. Escalating U.S. involvement in this conflict—or any conflict—should be guided by an idea about how to bring the war to an end. In this case, that would have required demonstrating that Ukrainian strikes inside Russia using U.S. systems are part of an integrated strategy to end the war on terms favorable to Ukraine and the United States.

That end will come, as the administration itself has repeatedly stated, at the negotiating table. In a bargaining process, coercive measures can be used as leverage. You impose military costs on your opponent with the goal of making them do what you want, not merely to counter their latest maneuver. But Ukraine and the West have shown no signs of being ready to start bargaining with Russia. And imposing costs absent a bargaining process makes further escalation inevitable. As Thomas Schelling, the guru of military coercion, noted, “If [our enemy's] pain were our greatest delight and our satisfaction his greatest woe, we would just proceed to hurt and to frustrate each other.”

This spiral dynamic—of unrelenting Russian aggression and ever-increasing Western military support for Ukraine to counter Moscow's momentum—has been ratcheting up nearly two and a half years. Without a bargaining process, it might continue for years to come. And someday, one side or the other might finally stumble over an actual red line, which could lead to exactly the major escalation the Biden administration has been trying to avoid.

In the meantime, Ukraine will continue to suffer and the costs of the war to the West will continue to mount. There has to be a better way to manage the most consequential military conflict in a generation.

Samuel Charap is distinguished chair for Russia and Eurasia policy at RAND. Jeremy Shapiro is director of research at the European Council on Foreign Relations.

This article was originally published on Rand.
Views in this article are author’s own and do not necessarily reflect CGS policy.