Putin often cites Russia’s ‘nuclear doctrine’ governing the use of atomic weapons. But what is it?

Since Russia invaded Ukraine in 2022, President Vladimir Putin and other Kremlin voices have frequently threatened the West with its nuclear arsenal.

On Day 1 of the war, Putin said “whoever tries to impede us, let alone create threats for our country and its people, must know that the Russian response will be immediate and lead to consequences you have never seen in history.”

Over nearly 2 1/2 years of fighting, the West has given Ukraine billions of dollars of advanced weapons, some of which have struck Russian soil. And while there have been more Kremlin threats — and even the deployment of battlefield nuclear weapons in Belarus, just over the border from Ukraine — so far it has remained only a blunt message.

What could finally trigger a nuclear response?

Asked that in June by international news agencies, Putin pointed to Russia’s so-called nuclear doctrine.

“Look what is written there,” he said at the St. Petersburg session. “If somebody’s actions threaten our sovereignty and territorial integrity, we consider it possible to use all means at our disposal.”

Now Russian hawks are urging him to change the doctrine to lower the threshold for using nuclear weapons, and Putin says the document could be modified to take into account the evolving global situation.

Formally known as the “Basic Principles of State Policy on Nuclear Deterrence,” it was signed by Putin in 2020 and outlines when Russia could dip into its atomic arsenal, the world’s largest.

It describes nuclear weapons as “a means of deterrence,” noting that their use is an “extreme and compelled measure.” It declares that Russia “takes all necessary efforts to reduce the nuclear threat and prevent aggravation of interstate relations that could trigger military conflicts, including nuclear ones.”

The document states that “nuclear deterrence is aimed to provide comprehension by a potential adversary of the inevitability of retaliation in the event of aggression against the Russian Federation and/or its allies.”

Russia could use them, the doctrine says, “in response to the use of nuclear and other types of weapons of mass destruction against it and/or its allies, as well as in the event of aggression against the Russian Federation with the use of conventional weapons when the very existence of the state is in jeopardy.”

It says nuclear weapons could be used under the following specific situations:

— If reliable information is received about the launch of ballistic missiles targeting the territory of Russia or its allies.

— If nuclear weapons or other weapons of mass destruction are used against Russia or its allies.

— If an enemy attack with conventional weapons threatens Russia’s existence.

— If there are attacks on critically important Russian government or military facilities that could undermine the country’s retaliatory nuclear strike capability.

As Russia attacked parts of northeastern Ukraine near the city of Kharkiv, Washington has allowed Kyiv to use longer-range U.S.-supplied weapons for strikes in Russian territory in the border region. But these attacks have been limited in scope and would not seem to pose an existential threat that would fall under the nuclear doctrine.

However, the hawks in Moscow have pointed to a series of Ukrainian attacks on Russian air bases that host long-range nuclear capable bombers earlier in the conflict, as well as recent raids on early warning radars.

They say these circumstances would seem to warrant the use of nuclear weapons as laid out in the doctrine.

Russian officials haven’t commented on the attacks on the more sensitive targets. The early warning radars are designed to spot the launch of U.S. missiles to allow Russia to launch its own nuclear-tipped missiles before they are destroyed.