Amid Russian war crimes and Ukrainian tactical victories, there are increasing calls for the US and the West to outsource their policy on Ukraine to Kyiv.

At a press conference this month, National Security Adviser Jake Sullivan suggested this was already US policy. According to Sullivan, “we believe our job is to support the Ukrainians. They’ll set the military objectives, the objectives at the bargaining table … we’re not going to define the outcome of this for them. That is up for them to define and us to support them in.”

This idea is wrong and potentially dangerous. For the sake of both national interest and basic prudence, no country should delegate its Ukraine policy to Ukraine.

Western support for Ukraine has been a necessary condition of that country’s survival. If Kyiv wants critical Western assistance, it must hear Western advice as well. US assistance implicates us in this war and creates a US interest in the war’s terms of conclusion.

But that US interest in Ukraine is obviously not equal to the Ukrainians’ own interest in national survival, territorial integrity, and future foreign policy autonomy. Washington needs to communicate clearly to Kyiv its own strategic aims and the costs Americans are willing to incur to pursue them.

While Ukraine is suffering tremendously, Western citizens are also paying the price of this war. This falls into two main categories: economic damage and escalation risks.

The prospect of a serious global economic slowdown grows by the day, with sanctions on Russia contributing to skyrocketing energy prices, particularly in Europe. British households saw gas prices rise 54% recently, and there is little reason to expect relief any time soon. America’s pain at the pump is less dramatic but just as real. Disrupted wheat, sunflower oil, and fertilizer exports also threaten food supply chains to countries in the global South.

It is political malpractice to simply assume that these escalating costs can be borne forever.

While the war will eventually end, all current signs indicate it is likely to persist for months. As a recent Wall Street Journal analysis concluded, “Ukraine’s counterattacks and Moscow’s redeployment toward Donbas in Ukraine’s east suggest that both sides believe they can win, making it unlikely that peace talks will result in a deal anytime soon … That could be a recipe for a prolonged conflict.”

Economic costs pale in comparison to the risks of escalation, with nuclear war the possible final stage of any confrontation between the United States and Russia. Escalation risk is potentially manageable, but it has been elevated both by President Volodymyr Zelenskyy’s demands and President Joe Biden’s rhetorical missteps.

The Ukrainian president’s call for a no-fly zone earlier in the conflict would have brought the US and any NATO members that followed it into war with Russia. Biden should make clear to Zelenskyy that the US will not fight Russia for Ukraine, and that our appetite for incurring risk on Ukraine’s behalf is already at its outer limit.

Although Biden has stated this repeatedly, his erratic rhetoric has added additional uncertainty to a volatile situation.

The Western willingness to run risks on Ukraine’s behalf is not and cannot be unlimited. Washington’s levels of resource expenditure and assumption of risk needs to be matched to America’s strategic aims. The unfortunate fact is that more than two months into the war, it is unclear what outcome US policy is aimed at.

Is the US looking to guarantee Ukrainian independence, shatter Russian conventional military power, or provoke regime change in Moscow? If the White House has an answer, it has yet to satisfactorily enunciate it.

For its part, Ukraine’s strategic aim is looking more and more like an outright defeat of Russia, perhaps to include even the reconquest of Crimea. Not only would this require the West to run large risks and suffer economic pain for a long time to come, but it would also raise the question of how Vladimir Putin’s Russia, facing a major defeat, would be likely to react.

Do we expect Putin, the man in charge of the world’s largest strategic nuclear arsenal, whom we regularly hear is psychotic or detached from reality, to view outright defeat with equanimity? Or is something much darker, like the use of tactical nuclear weapons in Ukraine, a real possibility?

Giving a blank check to a weaker partner with vital interests of its own is never sound statecraft. The US can manage the escalation risks in Ukraine. But the same US, as the key enabler of Ukraine’s defense, can and must have a say in when and how this war ends.