Since the invasion, the alliance has appeared unshaken—despite Moscow’s military failures, its isolation by the West, and the damage the war has brought to the Russian economy from international sanctions and the loss of major export markets for natural gas. The remarkable resilience of the partnership is significant, potentially not least as the foundation of a bloc opposing the West in a new Cold War between democracies and autocracies. Still, China continues to refuse Russia any military assistance against Ukraine, and just last week Beijing’s ambassador to the EU insisted that China wasn’t on Putin’s side in the war at all—and that the phrase “no limits” was just rhetorical. So what’s the status of the relationship, exactly?

Eyck Freymann is the author of One Belt One Road: Chinese Power Meets the World. To Freymann, the close connection between Xi and Putin, and the close alignment between Beijing and Moscow in the years and months leading up to the war, have taken very complicated turns now. Russia is overextended and isolated, needing all the support it can get from its most powerful ally in the world. And China is anxious, needing for its own sake to ensure Putin remains in power while managing increasingly fraught relations around the world—which Russia’s blunder in Ukraine continues to make only more difficult. Meanwhile, neither Beijing nor Ukraine’s allies in the capitals of the West want China to get directly involved in the war—but depending on what happens on the battlefield, none of them may be able to prevent it.

Eyck Freymann: This now-infamous meeting prior to the invasion, where Xi Jinping and Vladimir Putin agreed on their countries’ “no limits” friendship, was a pivotal moment.

Before that, relations between China and Russia had been improving since the mid-1980s—and that had accelerated since 2013, mainly thanks to the unusually close personal relationship between Xi and Putin. The two have met more than 30 times. They know one another better than any other world leaders of similarly sized countries do.

But the proclamation of a “no limits” partnership was important, because China and Russia have been divided, historically, by some real conflicts of interest—as much as Beijing and Moscow have tried to downplay these conflicts and project solidarity to the West.

They have serious clashes of interest in Central Asia. They have a 2,600-mile border and a history of conflict along it. The Chinese leadership has long believed it was the victim of bad Russian-brokered treaties that led to them losing lot of land—in Manchuria, modern-day Mongolia, and Siberia. The two countries almost came to blows in the 1960s. And the Chinese have never forgotten any of it.

Xi has made it clear that, with the way he sees the world redividing into blocs—what he calls the “great change unseen in a century”—China can’t do without Russia. Among other reasons: If there were to be a war with the United States in the Pacific, China would need land corridors to access energy and rare minerals, in order to keep its economy functioning. China doesn’t have many other close partners—apart from Pakistan, North Korea, Laos, and Cambodia. So when Putin invaded Ukraine, Xi couldn’t just abandon him.

At the same time, the U.S. has threatened credibly that, if China provided Russia with any lethal aid or formal support, China would become subject to direct sanctions—and probably indirect sanctions as well. Depending on how U.S. retaliation were designed, it could badly set back China’s tech sector and potentially even destabilize the Chinese banking system. And Washington could threaten to send more weapons to Taiwan.

So China has tried to play both sides of the conflict, maintaining an ambiguous position that leans toward Russia. In the meantime, the relationship between China and Russia has deepened, with Russia becoming more dependent on China as a buyer of Russian energy and a supplier of Chinese microchip technology.

Still, we shouldn’t overstate China’s willingness to follow Russia into the Ukraine sinkhole. China has other considerations to attend to, including managing its relationship with Europe. And so far—while it’s provided Russia with all kinds of assistance short of lethal aid—there’s a threshold Beijing has refused to cross.

“From the Chinese perspective, the quandary is that Putin can’t be allowed to lose in so humiliating a way that there’d then be a significant risk of Russia cracking up. China is very concerned about the prospect of failed nuclear states on its border. It has enough experience dealing with erratic nuclear-armed characters in neighboring states, North Korea and Pakistan. It also knows that a Russian breakup would be bad for its interests in Central Asia and potentially bad for its own internal security—not to mention bad for Xi’s domestic position, because he’s put so much political capital into his relationship with Putin.”

“If there’s a big Ukrainian breakthrough on one of the two major battle lines during the counteroffensive likely to start later this month—the Svatove line in the North or the Zaporizhzhia line in the South—and the Russian position starts to crumble, it will be a huge problem for China. We know from public sources that China is very concerned about a Russian battlefield collapse endangering Putin’s domestic position—and so, Beijing’s interests. In that scenario, the Chinese might feel compelled to enter the conflict openly by providing Russia with lethal aid. So far, they’ve been deterred by U.S. threats of sanctions. But a real prospect of Russia falling apart would be just too pressing for Chinese security interests for the threat of sanctions to outweigh it.”

“The war has also shown the West’s ability to pull together and impose sanctions that have some bite—and to maintain unity and sustain aid. But the U.S. government’s unwillingness to put boots on the ground, despite its support for Ukraine, suggests that it’s prioritizing the Indo-Pacific theatre over the European theatre. The Russian invasion has actually helped spur a consensus between Democrats and Republicans on supporting Taiwan. U.S. policy on the issue is still formally ambiguous, but it would be a lot more politically embarrassing now for the U.S. simply to abandon Taiwan than it would have been just a couple of years ago. That’s a major change.”