In the aftermath of statements by Russian President Vladimir Putin Wednesday threatening to use nuclear weapons in the war in Ukraine, US officials have made clear they are actively discussing the possibility that the conflict will erupt into a nuclear exchange.

“We have communicated directly, privately at very high levels to the Kremlin that any use of nuclear weapons will be met with catastrophic consequences for Russia, that the United States and our allies will respond decisively, and we have been clear and specific about what that will entail,” US National Security Advisor Jake Sullivan told moderator Margaret Brennan on the CBS interview program “Face the Nation” Sunday.

“And it is a matter that we have to take deadly seriously, because it is a matter of paramount seriousness, the possible use of nuclear weapons for the first time since the Second World War,” he added.

Later that day, the New York Times reported that US officials believe the chances of nuclear escalation “are significantly higher than they were in February and March.”

The Financial Times added that the US and its allies are “increasing nuclear vigilance and deterrence, according to five western officials who spoke under the condition of anonymity because of the sensitivity of the matter.”

The FT also reported, “The US had also discussed scenarios with the Ukrainians about possible nuclear use and walked through ‘protection and safety,’” citing a high-level official.

In his appearances on the US Sunday talk shows, Sullivan confirmed a report published in the Washington Post Thursday that US officials had sent “private communications to Moscow warning Russia’s leadership of the grave consequences that would follow the use of a nuclear weapon.”

Sullivan made these threats more explicit. He told “Meet the Press” moderator Chuck Todd the consequences would be “catastrophic if Russia went down the dark road of nuclear weapons use.”

In response to request for clarification from Todd, Sullivan continued, “If Russia crosses this line, there will be catastrophic consequences for Russia. The United States will respond decisively.”

Asked by Todd whether the repeated use of the term “catastrophic” means “as bad as he could imagine,” Sullivan responded, “Russia understands very well what the United States would do in response to the use of nuclear weapons in Ukraine because we have spelled it out for them, and I will leave it at that today.”

In other words, while the Russian leadership has, according to Sullivan, been informed of the consequences of the Russian use of nuclear weapons in Ukraine, the American people, who stand to be incinerated if the United States were to initiate a full strategic nuclear exchange, are to be left in the dark.

The escalation of tensions came as Russia held referendums in Luhansk, Donetsk, Kherson and Zaporizhzhia, four regions of Eastern Ukraine under its military control, for joining the Russian federation. The third day of voting was held Sunday.

On Saturday, Russian Foreign Minister Sergei Lavrov said that any regions annexed to Russia will be “under the full protection of the state,” implying that Russia would respond to any attacks on them with the use of nuclear weapons.

The Russian parliament could potentially move to incorporate the provinces into the Russian Federation on Thursday, and Putin is tentatively planning to address parliament on Friday.

In an interview with CNN, British Prime Minister Liz Truss made clear that the threat of nuclear escalation by Putin would not diminish UK involvement in the war. “We should not be listening to his saber-rattling and his bogus threats. Instead, what we need to do is continue to put sanctions on Russia and continue to support the Ukrainians,” Truss said.

Sullivan’s threats were accompanied by a full court press in the US media rationalizing the potential use of nuclear weapons in the conflict.

In perhaps the most egregious example, New York Times columnist Ross Douthat mused that “Kyiv might be willing to accept an unusual degree of nuclear risk, even absorb a nuclear strike, for the sake of its own territorial integrity. In a battle for their very freedom, the Ukrainians … want their children to look back and say that in the greatest crisis, the blood of their fathers ran strong.”

In a previous commentary on the World Socialist Web Site, we wrote that the strategists and propagandists of US imperialism see the people of Ukraine as “cannon fodder.” There is no greater confirmation than the suggestion that the people of the impoverished Eastern European country would be happy to “absorb” a nuclear attack potentially capable of killing millions of people.

In no section of the US political establishment has the increasingly obvious reality that the conflict is rapidly threatening to escalate into a nuclear war been treated as an incentive to push toward a negotiated settlement of the war, which has already killed tens of thousands of people and displaced millions.

Rather, the US is treating any Russian escalation of the conflict in the wake of the military debacle in northern Ukraine as an opportunity to further escalate its own involvement in the war. US officials, according to an op-ed Sunday by Times columnist David Brooks, wish to “continue to supply Ukraine with weapons, maybe even including tanks and advanced fighter planes. Those systems are apparently on the table.”