Rep. Mike Turner, ranking Republican on the House Intelligence Committee, complained that though Biden administration officials “have been publicly making statements of commitments to give Ukraine the tools and weapons to defend themselves, they’ve been very slow to do so. That, of course, has cost Ukrainian lives.”

Moreover, Turner forgets that his most fundamental duty is to Americans, not Ukrainians. The latter are entitled to set their own destiny without foreign interference, but Washington is obligated not to intervene militarily on their behalf absent a compelling U.S. interest, meaning a threat to American security. The most serious danger posed to the U.S. by the ongoing conflict in Ukraine is the possibility of our being dragged into war with Russia.

Moscow would not defeat America in a conventional war, though the former’s armed services likely would do better defending their homeland than attacking their neighbor. However, Russian doctrine envisions earlier use of nuclear weapons in response to U.S. conventional superiority, a reverse of the Cold War balance in Europe. And Ukraine matters much more to Moscow than Washington, hence Vladimir Putin’s many complaints over NATO expansion, most famously at the 2007 Munich Security Conference.

This makes Turner’s demand that the Biden administration confront Russia particularly misguided. Turner complained that President Biden “seems almost timid and afraid of what Russia may do as opposed to being appalled at what Russia is doing,” and insisted that Biden “needs to be able to stand up to [Putin] and to say that the United States certainly will deter Russia and all threats from them.”

Washington should deter threats—to America. Better, however, to avoid a potential war, whether advertent or inadvertent. International relations often is a complicated game of chicken. The U.S. and Russia sparring over the Ukraine conflict is a nuclear version of chicken, and Moscow possesses an advantage. It is the weaker power with more at stake, and has an incentive to make bigger bluffs and take bigger risks. If America’s survival were at stake, Washington might have cause to call Putin’s bet. But not when the U.S.’s stakes are so small.

The Atlantic Council’s Barry Pavel also dismissed Biden’s cautious stance: “There have been other cases where U.S. and Russian forces have unfortunately come into friction and World War III didn’t start.” Thus, he added, “There are hundreds of options that could be done between what NATO is doing now and risking World War III.”

This is certainly true—not everything the U.S. could do would trigger a Russian military response. For instance, the U.S. and its European allies already have provided Ukraine with lethal assistance without expanding the war. Some hawks have pointed to the 2018 incident in which pro-Assad forces, including Russian Wagner Group mercenaries, attacked a U.S. base in Syria. Although some 200 to 300 were killed, Moscow disclaimed any responsibility and did not retaliate. Decades before, Washington provided substantial aid—including Stinger missiles—to the Mujahideen, which led to thousands of Soviet casualties and did not prompt Russian retaliation.

However, the line separating good and bad bets is both invisible and unpredictable. Moreover, the Russian red line is likely to shift as Moscow finds its Ukraine mission becoming more difficult. Most important, the latter mission reflects core Russian interests, in contrast to most of the other examples provided. Putin likely views achieving victory over Kiev as the equivalent of defending Russia, making Moscow likely to respond more quickly and severely to seemingly less significant provocations.

Pavel worried that failing to take a tougher stance might weaken our ability to deter Russia: “Have we convinced the Russians that in fact we are determined to honor the Article Five guarantee and protect every inch of NATO territory?” However, the U.S. and its European allies made very clear that Ukraine is not part of NATO and therefore does not enjoy a NATO security guarantee. Moreover, Moscow’s strategy shift—pulling back forces from Kiev and concentrating on the Donbass—suggests that even Putin has come to realize his military’s limitations. The Russian military’s costly failure to achieve the Putin regime’s initial objectives has dramatically reduced the likelihood of further aggression by Moscow.

Even more unhappy are members of the Zelensky government. In March, Ukrainian Foreign Minister Dmytro Kuleba complained that the E.U. was “backsliding back to its normality where it cannot decide on strong and swift action.” Zelensky also has chided friendly governments for failing to implement toughen sanctions, expand and accelerate weapons transfers, and even wage war on Russia.

Of course, the Ukrainians have no reason to favor reason and moderation. A nation under attack naturally desires as much aid as possible. Truth be told, Ukrainian officials would be more than pleased if their actions triggered allied involvement in the conflict. This should come as no surprise and is no reason to criticize Ukraine. If America, which won its independence with French aid, were under attack, I would ask—even demand—that friendly states do everything possible for the U.S. Perhaps the most celebrated instance of a foreign nation doing the same was the United Kingdom in World Wars I and II. Winston Churchill had to work and wait more than two years after Germany attacked Poland for America’s entry into World War II.

Ultimately, Washington must make its decision on the basis of American rather than Ukrainian interests. Most importantly, the U.S. should not voluntarily enter the Russo-Ukrainian war. That obviously precludes implementing a no-fly zone, which would require shooting down Russian aircrafts over Ukraine and probably in Russia, as well as Russian suppressing air defenses. Proposals for “humanitarian corridors” and “peacekeeping forces” would be similarly dangerous, and would almost certainly trigger a military response by Moscow, with further escalation possible, even likely. All these steps would invite a shooting war with a nuclear-armed power, which could easily lead to World War III.

Others, such as Ivo Daalder of the Chicago Council for Global Affairs, propose that the U.S. and NATO should retaliate if Moscow uses biological, chemical, or nuclear weapons. Such an attack from Russia would be atrocious, but not worth the risk of responding and triggering a truly horrific conflict between the U.S. and Russia. As the weaker power, Moscow can ill afford to back down. And since it possesses escalation dominance in the form of nuclear weapons, it need not back down.

Moreover, success in Ukraine matters much more to the Putin government than to Washington and especially the American people. And, realistically, it would be the U.S., not NATO’s European members, that would be charged with striking Russian units and responding to any Russian retaliation. Although the U.S. should be prepared for use of biological, chemical, or nuclear weapons against fellow alliance members that it has promised to defend, it would be foolish to trigger a retaliatory cycle over Ukraine.

So far, the U.S. and European governments have concentrated on providing the Ukrainians with weapons and other military materiel. Doing so is well within the “rules of the game” between great powers. Washington did the same to the Mujahideen fighting Soviet troops, and Moscow did so to the North Vietnamese forces fighting American troops.

However, when a country distributes arms, it normally does so with plausible deniability. That is an important problem with proposals to transfer Polish MiGs to Ukraine: It would be difficult to fly aircraft into Ukraine surreptitiously. Countries that overtly distribute weapons risk the possibility that the enemy will attempt to interdict the traffic. Moscow itself has called arms shipments “legitimate targets.” Russia could even claim the right to strike weapons stored in or in transit through neighboring NATO members, most obviously Poland. Such attacks would likely trigger allied retaliation, which would create an incendiary situation.

Kuleba criticized any hesitation at filling Kiev’s military wish list: “Those who make up these artificial divisions in their minds—we can give this, but we cannot give that—they only extend the suffering of Ukrainians, they contribute to the toll of dead civilians, and they only facilitate the further destruction of Ukrainian cities and villages.” Most important for Western officials, however, is preventing their own citizens from sharing in Ukrainians’ suffering by minimizing the risk that the conflict spreads.

Washington already has provided substantial military support to Ukraine, including thousands of anti-tank and anti-armor weapons. The West is also training Ukrainian military personnel. U.S. and allied support obviously has helped turn Kiev’s armed services into an effective fighting force. Such military-personnel training is common, almost ubiquitous, internationally. Intelligence sharing is similarly widespread. However, nations normally do not broadcast these activities, as President Biden seemed to in one of his many recent gaffes. There is good reason to continue these activities, while retaining plausible deniability.

Even as it commits to providing this assistance, Washington’s overriding aim should be to help bring the war to a close. If the war continues, helping Ukraine protect its people is important. However, that defense is a means to an end—reaching a stable peace that protects the country’s independence. The cost of prolonged conflict would be incalculable, especially for the Ukrainian people.

Washington’s principal obligation remains the defense of the American people. U.S. policy toward the Russo-Ukraine war should be shaped accordingly.

Doug Bandow is a senior fellow at the Cato Institute. A former special assistant to President Ronald Reagan, he is author of Foreign Follies: America’s New Global Empire.