On May 9th, Russian President Vladimir Putin presided over a parade and celebrations in Moscow, commemorating the seventieth anniversary of the end of the Second World War in Europe. All of Russia’s Western allies in the war were conspicuously absent. Putin was joined, however, by Chinese President Xi Jinping, and the procession prominently featured a detachment of Chinese troops.

The Chinese President came to Moscow for more than the victory parade. The day before, Xi met Putin at the Kremlin and inked a flurry of agreements to bolster their economic and strategic relationship, including pacts to boost the use of their own currencies in bilateral trade and increase Russia’s natural-gas exports to China. Putin said that China would help finance a high-speed railway between Moscow and Kazan, a much-needed upgrade to Russia’s infrastructure. One pact was specifically crafted to help Russia evade some of the pain of Western sanctions imposed as a result of the Ukraine crisis, by encouraging Chinese banks to lend billions to cash-strapped Russian companies. After the meeting, a pleased Putin said, "China today is our strategic key partner."

Putin and Xi have met often over the past two years, most recently, before this month, in Beijing, during November’s Asia-Pacific Economic Cooperation conference. The first official overseas trip that Xi took as China’s President, in early 2013, was to Moscow. The frequency of their official dialogues underscores how close the two countries are becoming. Their navies are engaging in joint exercises in both the east and the west. As Chinese companies venture onto the world stage, they are investing significant sums in Russia. Derek Scissors, of the American Enterprise Institute, estimates that, between 2005 and 2014, the total was twenty billion dollars. Trade has exploded as well, with ninety-five billion dollars’ worth of goods passing between the two countries in 2014, six times more than in 2003. That exchange will increase further as China’s industrial machine consumes more Russian energy resources. Last year, Russia’s Gazprom agreed to provide four hundred billion dollars of natural gas to China over thirty years.

There are many forces pressing Russia and China together. Starved of capital by Western sanctions, Russia’s economy has been pushed to the brink of crisis. The International Monetary Fund expects it to shrink by 3.8 per cent this year. China stands out as Putin’s only potential source of significant new funds, investment, and consumers that is not aligned with his Western detractors. Xi, too, could do with a new friend. In East Asia, he has aggressively asserted China’s territorial claims over disputed islands and borders, sending many of his neighbors running to the United States for support—­both long-time American allies like Japan and the Philippines and former antagonists like Vietnam. With China’s economy suffering its deepest slowdown in a quarter century, Xi is also on the lookout for new outlets for Chinese industry.

Their common interests go well beyond immediate convenience. The strategic relationship between China and Russia “is not only anti-West but anti-the international order that the West has been advocating for a very long time,” Gilbert Rozman, a professor emeritus at Princeton University, who has spent much of his career studying relations between the two countries, said. Putin dreams of recreating a sphere of influence once held by the Soviet Union, while Xi envisions an East Asia where Beijing is the No. 1 power. Both resent U.S. security arrangements that constrain them, and Western objections to their human-rights records. In April, Putin complained that superpowers like the U.S. “do not need allies. What they need is vassals. … Russia cannot live in this system of relations.”

Washington’s response to Putin’s designs on Ukraine has been to attempt to isolate him and force him to back down. Though China cannot substitute for the trade and finance provided by the West, at least not in the near term, a wealthy and willing Beijing, standing at the ready with funds and diplomatic cover, can throw Putin a lifeline—and make it more difficult for the West to pressure him. After last year’s Gazprom deal, one Russian lawmaker blustered that President Obama “should give up his policy of isolating Russia—it won't work.”

Still, the partnership between Russia and China is not one of equals. China is by far the stronger of the two nations, and is believed to drive hard bargains with Russian negotiators. The May 8th pact to draw Chinese bank lending to Russia, for instance, forces Russia to take on some of the risk. The imbalance has not gone unnoticed. “In so many ways, Beijing is not Moscow's friend so much as its loan shark,” a May 5th commentary in the Moscow Times said. Donald Jensen, a senior fellow at the Center for Transatlantic Relations at Johns Hopkins University, believes that there may be a limit to how chummy Putin and Xi can become. “There is no other way that this relationship can go than to China’s advantage,” Jensen said. “Over the long term, it perpetuates Russia’s general downward trajectory as a world power.”