International tensions in respect of outer space are beginning to add up. Russia has recently said it will stop cooperating with the European, American, and Canadian space agencies when it comes to the International Space Station — and that might be just the start.

“To be friends in space, we must be friends on Earth,” says director general of Russia’s space agency, Dmitry Rogozin, in an exchange with Chinese state media. “Russia and China are friends on Earth.”

In November, Russia tested anti-satellite technology that destroyed one of its own satellites and created extensive space debris. The test sparked international fury over space junk, which could ostensibly cause cascading collisions capable of creating enough junk to make lower earth orbit unusable.

That phenomenon is known as the Kessler Syndrome, a version of which was imagined in 2013 in the movie “Gravity.” Moscow’s recklessness also menaced the ISS. Could the timing — months before Russia invaded Ukraine — have been deliberate?

Together with Communist China, Moscow has plans for a robotic mission to an asteroid in 2024. The countries are coordinating a series of lunar missions intended to build a permanent lunar station as soon as 2027.

Construction on Beijing’s Tiangong space station — its first long-term space station — is also due to be complete this year. China will then be the only sovereign nation to host its own space station. Mr. Rogozin has signaled Moscow’s eagerness to collaborate.

It would be a mistake for Western leaders to treat these developments as separate from geopolitics. Since the end of the last Cold War, new real estate has been added to the geopolitical chessboard. Developments in space are the future of geopolitics.

In some sense, the future is already the present. For President Putin and the Chinese party boss, Xi Jinping, establishing a dominant position in space would be a boon for their “new era” of international politics. The territorial expansion they seek is not confined to Earth. 

The economic and propaganda advantages of such a gain would be significant. Beijing has said it would open its space station to commercial missions and activities. Commercialization is becoming an increasingly critical part of Beijing’s efforts to dethrone America as the leading space power. Some 78 commercial space companies now operate in China.

NASA is also seeking to commercialize the ISS. Such companies as Lockheed Martin, Blue Origin, and Voyager Space have all expressed interest. Yet commercialization could complicate ties with European partners.

For European partners could be barred from buying up American space services under the European Space Agency’s mandate to support Europe’s own space industry. Europe’s Space Agency is also considering its participation in the Sino-Russian lunar station.

Yet more significant than economic or soft power gains would be Beijing’s and, potentially, Moscow’s, ability to control terrestrial satellite-based operations — even those as simple as credit card purchases or directions obtained via global positioning systems.

To say nothing of their ostensible ability to interfere with and undermine American military operations. The United States Space Force has requested $24.5 billion in the 2023 federal budget, some 40 percent more than in last year’s request.

The jump is an encouraging reflection of the urgency with which the burgeoning Sino-Russian space alliance is increasingly being perceived. Equally encouraging is America’s successful hypersonic missile test in mid-March, and the budding cooperation on hypersonic missiles among America, Britain, and Australia. 

On Saturday Mr. Rogozin cautioned that Russia’s withdrawal from the International Space Station could cause the station to topple from the sky — conceivably crashing, in the event, onto Europe or America.

Whether Mr. Rogozin intends his remarks to be sarcastic or in earnest, the time to play catch-up ball was yesterday. The advice for America and its partners is prenez garde, lest Moscow use the ISS as a space-age Molotov cocktail.