Russian President Vladimir Putin has said multiple times in the seven-month-long Ukraine War that he would use "all means available" to defend Russia.
"All means available" are understood to include nuclear weapons. When he says Russia, he also means four occupied and partially occupied regions of Ukraine that he has annexed.
Putin has framed the Ukraine War as a conflict with the West and his tone suggests he sees it as an existential war. His Foreign Minister Sergei Lavrov said at the United Nations (UN) that the West is trying to "destroy" Russia.
"And if the territorial integrity of our country is threatened, we will certainly use all the means at our disposal to protect Russia and our people. This is not a bluff," said Putin last week.
Here we explain how serious are Putin's threats, what's the Russian reasoinig behind threatening or actually using nuclear weapons, what nuclear weapons Putin might deploy, and how a nuclear attack would play out.
How seriously is West taking Putin's nuclear threats?
The West is taking these threats very seriously even as officials publicly say there is no evidence at the moment suggesting Russia is about to use nuclear weapons. The seriousness was demonstrated by none other than US President Joe Biden.
"I don’t think there is any such a thing as the ability to easily use a tactical nuclear weapon and not end up with Armageddon. [Putin is] not joking when he talks about the use of tactical nuclear weapons," said Biden, referring to the kind of weapons —tactical nuclear weapons— Putin might use.
Ukrainian President Volodymyr Zelensky has said the North Atlantic Treaty Organisation (NATO) should not wait for the Russians to strike first but should have a plan in place to deter such an action. He said NATO should employ "pre-emptive action".
Pre-emptive actions "are needed so that [the Russians] know what awaits them if they use nuclear weapons. Not the other way around, waiting for Russia's nuclear strikes and then saying, 'Oh, you've done that, then get this'," said Zelensky, as per Washington Examiner.
Most of the Russian nuclear launch sites are land-based and are therefore open for aerial and satellite-based surveillance. The United States, which is believed to be constantly monitoring the Russians, has not reported any evidence of launc preparation so far.
"Unlike the United States, which relies on submarines armed with intercontinental ballistic missiles for a large part of its arsenal, most of Russian nuclear forces consists of land-based missiles. Some are mounted on mobile launchers that can be tracked, but many are in silos, making launch preparations more difficult to discern," noted Associated Press.
How Putin might deploy nuclear weapons?
If and when Putin orders nuclear attack, he would likely deploy what are called tactical nuclear weapons (TNWs).
TNWs are short-range, low-yield nuclear weapons which are used in tactical situations in battlefields.
Strategic weapons refer to larger weapons carried by huge platforms like intercontinental missiles for strategic objectives of the broader war. Tactical weapons refer to short-range weapons carried by smaller missiles or rockets to fulfil particular battle objectives, such as stopping an overwhelming advance of convetional forces, such as armoured soldiers, or blasting off hills to make transform the battlefield.
The low-yield, however, does not mean these weapons are not dangerous. Most TNWs today are more powerful the bombs dropped by the United States on Japan in World War Two. Those bombs killed an estimated 1,30,000-2,00,000 people.
"Modern tactical nuclear warheads have yields up to tens of kilotons or potentially hundreds, several times that of the weapons used in the atomic bombings of Hiroshima and Nagasaki," noted Air Commodore (Retired) Rippon Gupta in an article for the United Services Institution of India (USI).
While there is no clarity on the range of such weapons, Gupta noted that it's known that Pakistan has tactical weapons for range as short as 60 kms. The usual upper limit of range for such weapons is believed to be 500 kms.
Though the range and damage would be lesser than the strategic nuclear weapons, it would still be significant as nuclear dust would fly outside of the intented target and could contaminate even the place it's fired from, thus leading to unintended consequences.
How a nuclear attack would play out?
Nuclear weapons, unlike conventional bombs or missiles, don't just affect the site of impact but also the wider vicinity of the site and wherever the wind travels.
"When a nuclear weapon explodes, it gives off four types of energy: a blast wave, intense light, heat, and radiation," says US Centers for Disease Control and Prevention (CDC).
The CDC says the nuclear explosion plays out in following steps:
1. When a nuclear weapon explodes, a large fireball is created and everything inside it vapourises, meaning every person there would die.
2. This creates a mushroom-shaped cloud and vapours in the cloud cools into dust-like particles —nuclear dust— and drops back to the earth as fallout.
3. This nuclear dust —the fallout of blast— is likely to be carried by the wind and can end up miles from the site of the explosion. Fallout is radioactive and can contaminate anything it lands on.
The CDC says that that it would not just kill from the blast but would cause blindness from intense light, burns from heat, and cause radiation sickness.
Moreover, water, food, soil, and crops would be contaminated from the nuclear dust falling with the wind.
Why would Putin use nuclear weapons?
If nuclear weapons cause such death and destruction, which Putin is undoubtedly aware of, why is he open to using them — particularly when nuclear dust and fallout could travel to mainland Russia and affect Russians as well?
This is because of what's called the strategy of "escalate to de-escalate". Simply speaking, this means that Russia would escalate the conflict to such a level that Ukraine and the West would stand down and not pursue the conflict further over fears of further escalation.
In nuclear warfare terminology, there is a concept of mutually assured destruction (MAD), which means that if one side uses weapons, the other would also use it and it would mean both sides destroy each other. To avoid MAD, Putin appears to believes, the West would stand down and Ukraine would cease fighting, meaning Russia would win the war.
This is a dangerous gamble as it rests on the belief that the West would not respond. Moreover, if the West stands down, it would give a license to Russia, Iran, or North Korea to engage the West in further nuclear blackmail.
"Whether or not it's a bluff, Putin’s 'escalate to de-escalate' doctrine has been scary enough to keep the US and NATO from going toe-to-toe with the Russians in a no-fly zone over Ukraine," reported Examiner in March.
How would West respond to Putin's nuclear attack?
The West might respond to any nuclear attack with a tit-for-tat attack, short of attacking Russian mainland.
"What you're trying to do is control the escalation, so if they hit you, you are going to have to respond — and you want to respond in such a way that prevents their further response. If you respond too weakly, well, have you really deterred them from responding? Or have you encouraged them? You make it very specific," said Arms control export Joe Cirincione to Examiner, adding such a response would target, for example, the actual air base in Russia from which the strike originated.
He added, "So you're not targeting Putin. You're not targeting Moscow. You’re going after the people who launched a strike. It’s a very specific escalation."
There is another line of thought that the West would go ahead with harder sanctions instead of nuclear strike in response. But this is likely to be ineffective as sanctions so far have not stopped Russia from waging a war.