Over four years after Russian President Vladimir Putin’s disastrous full-scale invasion of Ukraine, the West is still sending mixed messages to the Kremlin. Many Western leaders talk tough, arm Ukraine, impose sanctions, and warn Moscow against further aggression. Yet while Russia continues to immiserate Ukraine and Putin carries out an increasingly reckless campaign of provocations on NATO territory, those same governments—still struggling to wean themselves off of Russian oil and gas—often seem more worried about whether their response might be considered escalatory than about Russia’s own actions.
This signals to Putin that he has plenty more runway for an asymmetric campaign of terror in Europe. Still, Putin has miscalculated the resolve of his adversaries before, such as in his expected three-day “special military operation” to conquer Ukraine, and he may again miscalculate the limits of NATO’s tolerance. The accretion of sub-threshold attacks may, when added together, end up crossing a threshold for more aggressive collective defense. Some estimates of the combined scale of Russian sabotage across Europe reveal over a hundred attacks, including potentially devastating ones in Germany last month, and the trajectory is increasing. A better strategy to reverse this trend would clarify concrete costs for Putin up front: Real red lines are usually identified only in hindsight.
Over four years after Russian President Vladimir Putin’s disastrous full-scale invasion of Ukraine, the West is still sending mixed messages to the Kremlin. Many Western leaders talk tough, arm Ukraine, impose sanctions, and warn Moscow against further aggression. Yet while Russia continues to immiserate Ukraine and Putin carries out an increasingly reckless campaign of provocations on NATO territory, those same governments—still struggling to wean themselves off of Russian oil and gas—often seem more worried about whether their response might be considered escalatory than about Russia’s own actions.
This signals to Putin that he has plenty more runway for an asymmetric campaign of terror in Europe. Still, Putin has miscalculated the resolve of his adversaries before, such as in his expected three-day “special military operation” to conquer Ukraine, and he may again miscalculate the limits of NATO’s tolerance. The accretion of sub-threshold attacks may, when added together, end up crossing a threshold for more aggressive collective defense. Some estimates of the combined scale of Russian sabotage across Europe reveal over a hundred attacks, including potentially devastating ones in Germany last month, and the trajectory is increasing. A better strategy to reverse this trend would clarify concrete costs for Putin up front: Real red lines are usually identified only in hindsight.
Much of Europe’s hesitancy to get tougher with Russia, a nuclear power—as it consistently reminds everyone—is rooted in a fear of where tit-for-tat escalation might take them. Since the beginning of the full-scale invasion, European leaders have worried that one retaliatory step could provoke another, creating an action-reaction spiral that ends in direct conflict between NATO and Russia.
But this conception of escalation is largely vertical and immediate, while Moscow is escalating horizontally and incrementally. Russia operates below the threshold of conventional war by salami-slicing European security: an arson attack here, a severed undersea cable there, GPS jamming, a cyberattack, a drone incursion. The problem in confronting Russia in the gray zone is that each incident does not seem to warrant a major response, and NATO member countries are loath to act more decisively without clear NATO backing. The cumulative pattern gradually normalizes Russian violence inside Europe and threatens to condition European publics to regard such insecurity as the cost of supporting Ukraine. Putin’s purpose in his European gray-zone campaign is to separate Kyiv from its backers by persuading nervous publics that Ukraine is not worth risking their own security. In an echo of the dilemma of Cold War extended deterrence, Putin wants Europeans to conclude that Kyiv is not worth putting their own security at risk.
In September 2024, the chief of Britain’s foreign intelligence service observed that Russian intelligence had “gone a bit feral.” In March, the European Union more specifically described Moscow’s activities as a “persistent, coordinated and long-standing” hybrid campaign encompassing sabotage, arson, cyberattacks, interference, and attacks on critical infrastructure. These characterizations are correct, but Moscow has become even more reckless. In August, an arson attack struck Milrem Robotics, an Estonian defense company whose unmanned systems are supplied to Ukraine. Estonian authorities are investigating Russian involvement. Slovak police subsequently thwarted an incendiary attack against a drone-production facility.
In Poland, Prime Minister Donald Tusk confirmed that a fire at a factory producing drone components for the Polish and Ukrainian militaries was sabotage. Then, earlier this month, two Bulgarian nationals were arrested after incendiary devices were thrown at the Munich headquarters of defense-electronics manufacturer Rohde and Schwarz and drone manufacturer Helsing, although Russian sponsorship has not yet been proved. In early September, Danish intelligence warned that Russia is recruiting Danes to help prepare sabotage against defense companies supporting Ukraine, while Romanian intelligence announced that it had disrupted a Russian-coordinated operation targeting strategic military sites.
Yet despite all this, the response both from Washington and Europe has been woefully insufficient. On Aug. 25, CIA Director John Ratcliffe visited Moscow to reportedly warn his Russian intelligence counterparts against attacking NATO. Yet the warning came with no publicly articulated consequence. Privately conveyed consequences might have lacked credibility in any case, given Trump’s apparent affinity for Putin and his consistent favoring of Russian talking points regarding Ukraine. Whatever deterrent message Ratcliffe had tried to convey was muddied further less than two weeks later when Trump’s envoys Steve Witkoff and Jared Kushner exchanged a cordial welcome with Putin at the Kremlin, where the Russian leader rehashed the same talking points about the “root causes” of the war. The next day in Kyiv, a tone-deaf Kushner spoke of Putin’s “aspirations” for Russia.
The same one-step-forward, one-step-back pattern is visible in Washington’s dwindling military support for Ukraine. At the NATO summit in Ankara on July 8, Trump publicly told President Volodymyr Zelensky that the United States would grant Ukraine a license to manufacture the desperately needed Patriot air-defense interceptors, emphasizing the defensive nature of the system. But a few weeks later he reversed himself, declaring that the United States had “not agreed” to do that. All Putin needs to do is wait a moment for Trump to perform one of his almost inevitable reversals.
Germany’s patience with Putin, meanwhile, seems inexhaustible. While Berlin has become one of Ukraine’s indispensable supporters, Chancellor Friedrich Merz tolerates one outrage after the next on German soil. It is true (and proper) that Germany has provided tens of billions of euros in military assistance to Kyiv, from Leopard tanks and artillery to air-defense systems while backing repeated rounds of sanctions against Moscow. Germany has spoken increasingly bluntly about the Russian threat, but Berlin’s rhetoric has outpaced any real response.
As its conventional ground campaign stalled in the Donbas, Russian violence has been gaining pace in Europe. In July 2024, an incendiary device hidden in a DHL parcel caught fire at Leipzig airport shortly before being loaded onto an aircraft bound for Britain. Germany’s domestic intelligence chief later said the country had narrowly escaped a potential plane crash in which, presumably, many people on the ground could have died, not to mention the aircraft’s crew. Despite the potentially catastrophic consequences, Berlin’s immediate response was tepid, failing to publicly attribute the attack to Russia.
Still more German prevarications came in response to Russian provocations. This August saw multiple attempted drone attacks in the same airport against a Ukrainian cargo plane. Before Germany formally blamed Russia for the plot, Merz boldly promised that those responsible for such attacks against Germany “will pay.”
But after Interior Minister Alexander Dobrindt announced that the evidence clearly pointed to Russian responsibility, the reckoning proved desultory. Berlin stated that Germany would respond “resolutely, prudently, and proportionately, without escalating,” but in response to what could have been an enormous explosion at a busy airport, the Germans closed a Russian consulate and cultural center, expelled diplomats, tightened visa restrictions, and promised to support further financial sanctions. No one in the Kremlin is likely to have lost any sleep over this.
The West’s mixed messages may be described as “balanced” by politicians, or some strategists might approve of their “ambiguity” to provide “flexibility,” but not only do they prolong the status quo, they invite further escalation. In aggregate, these vacillations signal weakness. If defending NATO territory from Russian gray-zone attacks, imposing meaningful costs for sabotage, and demanding accountability for aggression in and beyond Ukraine are themselves treated as dangerously escalatory, then Putin has already achieved part of what he wants: a Europe deterred by its own fears, and consequently a freer hand for Putin himself in what he views as his own sphere of influence in the former Soviet Union.
The answer is not necessarily conventional military responses, but these could be part of a greater predictability of consequences that must be credible and communicated in advance. For instance, Berlin does have a “resolute” pathway to get its deterrent message across to Moscow, and the debate over providing Ukraine with Taurus cruise missiles has become the acid test of German resolve. In response to the 2024 and 2026 Leipzig airport attacks, Merz should finally provide Ukraine with Taurus—the same ones that he criticized his predecessor, Olaf Scholz, for withholding but even now cannot bring himself to transfer.
Berlin claims that it is already supporting Ukrainian deep-strike capability without the Taurus, but sending a new system linked to specific acts of Russian sabotage would communicate the right signal of credible consequences. That Berlin still fails to do so is now sending a signaling message that gives comfort to the Kremlin. Putin himself must wonder what threshold he has to cross in order for the Germans to unlock their own deep-strike capabilities for Ukraine.
The addition of advanced weapons systems in response to specific violent acts could be joined by more specific financial punishment linked to Russian misbehavior. Given Brussels’s reticence to confiscate the 200 billion euros in immobilized Russian sovereign assets at Euroclear in one stroke, it could instead offer a claims mechanism that draws on this money as damage is adjudicated from both Ukrainian and European claims. The Council of Europe’s Register of Damage in The Hague is already cataloguing Ukrainian losses, and a parallel effort could take filings from European states for Russian sabotage on their own territory and pay damages.
Such a fund could cover severed undersea cables, arson, flight cancellations due to drone incursions, jammed navigation, and business losses due to Russian cyberattacks. Every act of Russian destruction, in Ukraine or in Europe, would then write its own invoice payable from Moscow’s frozen account. Metering the drawdown in this way would convey to Putin that his attacks in Ukraine and Europe have real financial costs that he is imposing upon Russia.
Washington has a real interest in restraining Russian aggression abroad and, more than any other country, has the means at its disposal if it could muster the political will. Unfortunately, Putin is so confident in the absence of any meaningful censure from the Trump administration that, according to the U.S. Department of Justice indictment, Russian intelligence officers were arranging for the assassination of a Russian dissident in the United States and soliciting U.S. citizens as assassins abroad.
Yet the U.S. could act across domains (i.e., land, maritime, cyber) to impose serious costs on Russian interests around the world. For instance, it could go much further with economic sanctions in third countries; could take more muscular action against the Russian shadow fleet; could undertake sophisticated cyberattacks to include disabling Russian intelligence-operated cyber-infrastructure; and intensify covert, financial, and diplomatic pressure on Russian extractive operations in Africa.
Moscow should know in advance that sabotage against a NATO country will generate a specific and meaningful cost that is better to be avoided. Deterrence does not require responding to every provocation with maximum force. It does require convincing Putin that continuing his gray-zone campaign will become more trouble than stopping it.
