What American actions in Ukraine might trigger a direct Russian attack on the United States or its allies? This is a critical question, as getting the answer wrong could result in an escalatory spiral that leads to nuclear war. Few would dispute that there is no greater U.S. security imperative than preventing Armageddon.
For many in the Biden administration, the best way to discover an answer to this question has been to experiment. Washington has over time gradually increased the sophistication and lethality of the weapons it is providing to Ukraine, assessing with each discrete new delivery whether any Russian retaliation will target the West.
As American assistance has graduated from anti-tank weapons to M1A1 Abrams tanks, and from shoulder-fired surface-to air-missiles to Patriot air defense batteries, the Biden administration has grown increasingly confident that the Kremlin’s “red lines” in Ukraine are not as sharply drawn as once feared. Despite its threatening rhetoric, Russia has shown no eagerness for a direct confrontation with NATO. According to a recent Washington Post report, Secretary of State Antony Blinken and National Security Adviser Jake Sullivan have both come to believe that the benefits of increasingly bolder American military support for Ukraine outweigh the potential risks. This growing confidence has prompted Biden to reverse his earlier refusals to provide F-16 fighter aircraft.
To many observers, this step-by-step approach to testing the limits of Russian tolerance is sensibly cautious. But it suffers from a potentially fatal flaw. A nation’s redlines – those that it will go to war to defend – are not always static. They can shift over time, depending on changing military fortunes and the domestic political pressures of the moment. An adversary’s actions that might be bearable in one set of circumstances can become quite intolerable in another. We are likely to discover that we have gone too far only after we find ourselves in a direct confrontation with Russia, not before.
Success in tiptoeing carefully up to Russian redlines also depends on a variable we only loosely control: Ukraine’s own military actions. Despite repeated U.S. admonitions against direct attacks on Russia, the Ukrainians have begun striking Russian territory through drone attacks and ground incursions, in some cases using NATO-supplied weaponry. With the longer-range Storm Shadow missiles the UK has recently provided, not to mention the F-16 fighter aircraft in the pipeline, Ukraine will have even greater ability to attack across Russia’s border.
Although the United States has strong reasons to avoid direct involvement in war against Russia, the Ukrainians may well believe that drawing Moscow into a clash with the US military is their best hope for victory. An American approach to preventing escalation that is premised on tight Ukrainian discipline looks increasingly unwise.
What might Russian escalation look like? Fortunately, it would probably not start with the use of tactical nuclear weapons. Putin’s broader geopolitical strategy depends heavily on courting China, India, Brazil and other non-Western actors. Preemptively crossing the nuclear threshold would invite near-universal condemnation, rendering Russia a virtual pariah internationally.
But Moscow has a number of options short of nuclear preemption that would nonetheless cause serious damage to the United States and NATO. Much of the Ukrainian war effort depends on America’s space-based communications, reconnaissance, and guidance systems that are vulnerable to Russian attacks. Russia highlighted this capability in November 2021, when it destroyed one of its own orbiting satellites with a ground-based interceptor missile — a demonstration that was almost certainly meant as a warning to the United States as tensions over Ukraine mounted. Although Moscow would expect Western reciprocation, Russia is far less dependent on space-based systems than is the United States.
There is little reason for confidence that either Washington or Moscow could contain any resulting crisis. Trust levels between the two governments are at all-time lows. Putin is under growing pressure from nationalist critics, who argue that his failure to strike back at the West has only encouraged more threatening military support for Ukraine. The Kremlin’s attrition strategy of slowly grinding down Ukraine’s capacity for war has been designed to achieve victory without fighting NATO directly, but it depends on the patience of the Russian people, which may wear thin if Ukraine continues to strike Russian territory.
In turn, Biden faces pressure from Washington hawks and East European allies convinced that standing up to Moscow will produce Russian concessions rather than escalation.
In this context, an experimental approach to testing Russia’s red lines is a formula for mission creep and a spiral into war between the world’s two largest nuclear powers. We should recall that Russia’s invasion began some two months after Biden declared on the White House lawn in December 2021 that he would not “accept anybody’s red lines,” and Washington subsequently rejected Putin’s demand that it forswear NATO membership for Ukraine. By invading, Putin has already demonstrated a willingness to back rhetoric with force, even if he so far has refrained from attacking NATO directly.
Rather than probing to discover how much we can get away with in Ukraine, we should be focusing on what is vital for America’s national security. Preventing escalation into a direct war with Russia is by far our most compelling interest. Ensuring that Russia does not re-subjugate Ukraine is both important and achievable without providing Ukraine with new, potentially provocative offensive capabilities.
By contrast, enabling Ukraine’s recapture of Crimea, prosecuting Russian leaders for war crimes, and enfeebling Russia’s military may be desirable in the abstract, but these goals are tangential to America’s security, and pressing to accomplish them will inevitably increase the risks of escalation.
Washington may believe that testing Russia’s appetite for war with the United States is sound policy. But we have better options. Now is the time to combine measured defensive support for Ukraine with a diplomatic offensive to end the fighting before it escalates beyond our control. The American people should insist on it.
