Ukraine keeps crossing Russia’s red lines. Putin keeps blinking.

Ukraine’s resistance to Russia’s invasion keeps crossing President Vladimir Putin’s red lines.

Kyiv’s lightning incursion into Kursk in western Russia this month slashed through the reddest line of all - a direct ground assault on Russia - yet Putin’s response has so far been strikingly passive and muted, in sharp contrast to his rhetoric earlier in the war.

On Day 1 of the invasion in February 2022, Putin warned that any country that stood in Russia’s way would face consequences “such as you have never seen in your entire history,” a threat that seemed directed at countries that might arm Ukraine.

If Russia’s territorial integrity were threatened, “we will certainly use all the means at our disposal to protect Russia and our people. It’s not a bluff,” he said a few months later in September. “The citizens of Russia can be sure that the territorial integrity of our Motherland, our independence and freedom will be ensured - I emphasize this again - with all the means at our disposal,” making a clear reference to Russia’s nuclear weapons.

But Ukraine’s punch through Russian defenses in the first foreign invasion since World War II exposed Russia’s military flaws and laid bare Moscow’s apparently illusory red lines.

Now some are again questioning the centerpiece of Washington’s Ukraine strategy: a slow, calibrated supply of weapons to Ukraine to avoid escalating tensions with Russia that critics argue has dashed Kyiv’s chances of driving Russia out and resulted in a grinding war of attrition with massive casualties.

Ukraine’s Kursk incursion “proved the Russians are bluffing,” said Oleksandr Danylyuk, a former Ukrainian intelligence and defense official, now an associate fellow with the Royal United Services Institute, a think tank in London. “It shuts down all of the voices of the pseudo experts … the anti-escalation guys.”

The attack was “risky,” he continued, “but it sent a very powerful signal and helped us change the narrative about Ukraine - that it is not able to win - and on the Russian red lines. Both narratives have been destroyed.”

Ukraine’s attacks have repeatedly crossed ostensible red lines: sinking Russia’s Black Sea flagship, Moskva; the 2022 Crimea Bridge blast; Storm Shadow missile attacks on the fleet headquarters in Sevastopol; the 2023 drone attacks on the Kremlin and Moscow; the assassinations of propagandists on Russian territory; and attacks on strategic air bases hundreds of miles from Ukraine.

The Western hardware being used by Ukrainian forces, HIMARS, tanks, ATACMS and F-16s, were all once red lines, too.

When Ukrainian drones struck Moscow in May 2023, hitting a Kremlin dome and closing major airports, Putin downplayed the problem, analyst Tatiana Stanovaya wrote at the time in an analysis for the Carnegie Endowment for International Peace.

“Within a few months, it seemed that the Kremlin’s red lines had either never existed or had become extremely mobile.” The Kremlin claimed to be unperturbed, she wrote, “even if it flies in the face of common sense.”

It was to become a striking pattern, yet the U.S.-led policy on military aid to Ukraine has remained timid, according to many analysts.

Boris Bondarev, a Geneva-based former Russian diplomat who resigned in 2022 to protest the war, said in an interview that Washington’s fear of triggering a direct military conflict with Russia had crippled the U.S. response, leaving its goals in the war unclear and projecting American weakness to Putin and other global adversaries.

“When you put your enemy’s red lines, so to speak, as the crucial factor of your own strategy, you will always be on the losing side,” he said.

Ukrainian President Volodymyr Zelensky, on Tuesday used the Kursk incursion to argue against Washington’s restrictions that bar Kyiv’s use of Western weapons to strike deeper at military targets in Russia - such as the air bases Russia uses for its devastating glide bomb attacks.

“We are witnessing a significant ideological shift - the naive, illusory concept of so-called red lines regarding Russia, which dominated the assessment of the war by some partners, has crumbled apart these days,” Zelensky said.

While Ukraine’s Kursk incursion has changed calculations, it has not shifted the fundamental balance in the war, with Moscow continuing its focus on eastern Ukraine, closing in on the city of Pokrovsk in Donetsk region, a key logistical hub that could pave the way for further Russian advances if it falls.

If Washington did allow Ukraine to strike military targets deeper within Russia with U.S. weapons, it would dash yet one more taboo, but Sergei Markov, a pro-Kremlin analyst, suggested that Moscow had already factored this in.

“In Russia, there is no doubt that such permission will be given,” he said. “Russia already considers that the decision has been taken by the U.S.”

“Russia tried to clearly draw these red lines, but the U.S., which is a participant in the conflict, decided that ‘We’re not going to cross any big red lines but only small ones,’” he said “They decided we are going to cut these red lines into dozens of small thin red threads, to cross them bit by bit so that there was no big event which could become a” cause of war.

A Russian academic with close ties to senior Moscow diplomats said the Russian leadership was taking the use of U.S. and Western weapons deeper in Russia “very seriously” but said it wasn’t clear whether a decision had been made on how to respond. He spoke on the condition of anonymity to discuss deliberations in Moscow frankly.

Russian authorities have been seeking to downplay the significance of the Ukrainian incursion and failure of its military leadership.

The presence of Ukrainian troops in 15 to 20 “little known” villages in the Kursk region was of “little significance” compared to Russian advances in Donetsk, Markov said. But if Ukraine occupied all of Glushkovsky district in Kursk or took the regional capital, Kursk city, “this would be a very big loss” that could force Putin to change his approach, he added.