Russia used its veto power at the United Nations Security Council (UNSC) on Wednesday to block a resolution sponsored by the United States and Japan to ban nuclear weapons in outer space.

China abstained from the vote, while the other 13 members of UNSC all voted in favor of the resolution.

Russia’s stated reason for exercising its veto was that the new resolution was unnecessary, because orbital nuclear devices and other weapons of mass destruction (WMD) were already prohibited by the 1967 Outer Space Treaty. 

The U.S. and Russia accused each other of playing dirty tricks and indulging in geopolitical theater by proposing or opposing the new measure, respectively.

U.S. Ambassador to the United Nations Linda Thomas-Greenfield said it was “baffling” for Russia to oppose a resolution that merely reaffirmed the 1967 treaty.

“Today’s veto begs the question: Why? Why, if you are following the rules, would you not support a resolution that reaffirms them? What could you possibly be hiding? It’s baffling. And it’s a shame,” she said.

White House National Security Advisor Jake Sullivan jumped in to second Thomas-Greenfield’s critique, and then answered her rhetorical question by accusing Russia of shooting down the resolution because it is “developing a new satellite carrying a nuclear device.”

Sullivan was alluding to comments by White House National Security Council spokesman John Kirby in February that Russia is developing a “troubling” new “space-based” anti-satellite weapon. Kirby divulged few details about this weapon, but he specifically stated it would breach the 1967 Outer Space Treaty.

Other comments from U.S. intelligence officials in February suggested Russia might be planning to launch a nuclear device into orbit that could be detonated to take out huge numbers of commercial and military satellites in the event of an escalating military confrontation.

One reason this concept is so “troubling” to U.S. military planners is that Russia might believe it could get away with detonating such a device without triggering a massive nuclear response, since there would be few human casualties or immediate environmental devastation.

The U.S. reportedly warned China and India in February that Russia would destroy their satellite networks as well if it ever detonated such a weapon, so it would be in their interests to notify Russian strongman Vladimir Putin that putting a nuclear bomb in orbit for any reason is unacceptable.

Thomas-Greenfield echoed those warnings in public in her remarks at the United Nations, advising the entire world to unite against orbital nuclear weapons because they could destroy “thousands of satellites operated by countries and companies around the world,” wiping out “the vital communications, scientific, meteorological, agricultural, commercial, and national security services we all depend on.”

“Regrettably, one permanent member decided to silence the critical message we wanted to send to the present and future people of the world: outer space must remain a domain of peace, free of weapons of mass destruction, including nuclear weapons,” said Japan’s U.N. ambassador Yamazaki Kazuyuki.

“Today’s vote marks a real missed opportunity to rebuild much-needed trust in existing arms control obligations. Now begins the work of righting that wrong,” the U.S. and Japan said in a joint statement after the vote.

Russian U.N. Ambassador Vassily Nebenzya responded on Wednesday that the new resolution was “absolutely absurd and politicized,” then criticized it for not going far enough because it focused on nuclear warheads instead of other space weapons.

“We want a ban on the placement of weapons of any kind in outer space, not just WMDs. But you don’t want that. And let me ask you that very same question. Why?” Nebenzya shot back at Thomas-Greenfield.

“Trying to depict Russia as a player with no interest in preventing an arms race in space who fails to observe the relevant obligations under international treaties is completely absurd,” he sneered.

The Russian ambassador darkly insinuated that the U.S. has long blocked a 2008 Russian-Chinese proposal to ban all weapons from outer space because it has plans to militarize space with non-nuclear ordnance. He denounced the UNSC resolution as a “cynical ploy” with “hidden motives.”