In a Sunday "60 Minutes" interview to air in full Sunday night, President Joe Biden issued a warning for Russian President Vladimir Putin to not "change the face of war" by employing either tactical nuclear or chemical weapons against Ukraine.
"Don't. Don't. Don't. You will change the face of war unlike anything since World War II," Biden said while speaking to CBS interviewer Scott Pelley. Biden was responding to a question from Pelley on what the US president's message would be if he learned that Putin was contemplating use of weapons of mass destruction.
Biden stopped short of saying expressly that the US would jump into the conflict more directly against Russian forces, but he stipulated "it'll be consequential" and that the end result would be: "They'll become more of a pariah in the world than they ever have been."
Without detailing a hypothetical American response, Biden explained that US action would depend on "the extent of what they do."
While there have been no indicators that the Kremlin has plans for such a dramatic and deadly escalation, also given that Moscow still hasn't technically declared formal war or national mobilization, the opening two months of the war saw widespread reports that Putin put the nation's nuclear forces on "high alert".
There have also been prior allegations issued by Ukrainian forces of Russian chemical weapons usage - but none of these earlier accusations was ever sustained or backed by evidence, or rose to the level of Ukraine's allies backing the charge.
Ukrainian officials have also more recently said that Russia is now using and still occupying Zaporizhzhya nuclear power plant for the sake of "nuclear blackmail" and to unleash "nuclear terror". At the start of August, UN Secretary-General Antonio Guterres said that the world is "one miscalculation away from nuclear annihilation" given the grinding Ukraine war, now seven months in.
He noted at the time that "We have been extraordinarily lucky so far" - and called for a broader stand-down of all nuclear-armed powers' arsenals:
Secretary General Guterres said the "luck" the world had enjoyed so far in avoiding a nuclear catastrophe may not last - and urged the world to renew a push towards eliminating all such weapons.
"Luck is not a strategy. Nor is it a shield from geopolitical tensions boiling over into nuclear conflict," he said.
The Russian side has voiced its own concern for the potential of nuclear escalation, but as part of comments directed at the West. Beginning in April, foreign minister Sergei Lavrov vowed that Russia would avoid using nuclear weapons at all costs - in response to headlines alleging Russian nuclear preparedness related to the Ukraine crisis. But Lavrov at the time also cited the danger of underestimating how rapidly things could spiral in Ukraine:
Russian Foreign Minister Sergei Lavrov warned the West on Monday not to underestimate the elevated risks of nuclear conflict over Ukraine and said he viewed NATO as being "in essence" engaged in a proxy war with Russia by supplying Kyiv with weaponry.
"I would not want to elevate those risks artificially. Many would like that. The danger is serious, real. And we must not underestimate it," he said.